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# 10 Easy Arithmetic Tricks

Math can be terrifying for many people. This list will hopefully improve your general knowledge of mathematical tricks and your speed when you need to do math in your head.

1. The 11 Times Trick

We all know the trick when multiplying by ten – add 0 to the end of the number, but did you know there is an equally easy trick for multiplying a two digit number by 11? This is it:

Take the original number and imagine a space between the two digits (in this example we will use 52:

5_2

Now add the two numbers together and put them in the middle:

5_(5+2)_2

That is it – you have the answer: 572.

If the numbers in the middle add up to a 2 digit number, just insert the second number and add 1 to the first:

9_(9+9)_9

(9+1)_8_9

10_8_9

1089 – It works every time.

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2. Quick Square

If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. Mulitply the first digit by itself + 1, and put 25 on the end. That is all!

252 = (2x(2+1)) & 25

2 x 3 = 6

625

3. Multiply by 5

Most people memorize the 5 times tables very easily, but when you get in to larger numbers it gets more complex – or does it? This trick is super easy.

Take any number, then divide it by 2 (in other words, halve the number). If the result is whole, add a 0 at the end. If it is not, ignore the remainder and add a 5 at the end. It works everytime:

2682 x 5 = (2682 / 2) & 5 or 0

2682 / 2 = 1341 (whole number so add 0)

13410

Let’s try another:

5887 x 5

2943.5 (fractional number (ignore remainder, add 5)

29435

4. Multiply by 9

This one is simple – to multiple any number between 1 and 9 by 9 hold both hands in front of your face – drop the finger that corresponds to the number you are multiplying (for example 9×3 – drop your third finger) – count the fingers before the dropped finger (in the case of 9×3 it is 2) then count the numbers after (in this case 7) – the answer is 27.

5. Multiply by 4

This is a very simple trick which may appear obvious to some, but to others it is not. The trick is to simply multiply by two, then multiply by two again:

58 x 4 = (58 x 2) + (58 x 2) = (116) + (116) = 232

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6. Calculate a Tip

If you need to leave a 15% tip, here is the easy way to do it. Work out 10% (divide the number by 10) – then add that number to half its value and you have your answer:

15% of \$25 = (10% of 25) + ((10% of 25) / 2)

\$2.50 + \$1.25 = \$3.75

7. Tough Multiplication

If you have a large number to multiply and one of the numbers is even, you can easily subdivide to get to the answer:

32 x 125, is the same as:
16 x 250 is the same as:
8 x 500 is the same as:
4 x 1000 = 4,000

8. Dividing by 5

Dividing a large number by five is actually very simple. All you do is multiply by 2 and move the decimal point:

195 / 5

Step1: 195 * 2 = 390
Step2: Move the decimal: 39.0 or just 39

2978 / 5

step 1: 2978 * 2 = 5956
Step2: 595.6

9. Subtracting from 1,000

To subtract a large number from 1,000 you can use this basic rule: subtract all but the last number from 9, then subtract the last number from 10:

1000
-648

step1: subtract 6 from 9 = 3
step2: subtract 4 from 9 = 5
step3: subtract 8 from 10 = 2

10. Assorted Multiplication Rules

Multiply by 5: Multiply by 10 and divide by 2.
Multiply by 6: Sometimes multiplying by 3 and then 2 is easy.
Multiply by 9: Multiply by 10 and subtract the original number.
Multiply by 12: Multiply by 10 and add twice the original number.
Multiply by 13: Multiply by 3 and add 10 times original number.
Multiply by 14: Multiply by 7 and then multiply by 2
Multiply by 15: Multiply by 10 and add 5 times the original number, as above.
Multiply by 16: You can double four times, if you want to. Or you can multiply by 8 and then by 2.
Multiply by 17: Multiply by 7 and add 10 times original number.
Multiply by 18: Multiply by 20 and subtract twice the original number (which is obvious from the first step).
Multiply by 19: Multiply by 20 and subtract the original number.
Multiply by 24: Multiply by 8 and then multiply by 3.
Multiply by 27: Multiply by 30 and subtract 3 times the original number (which is obvious from the first step).
Multiply by 45: Multiply by 50 and subtract 5 times the original number (which is obvious from the first step).
Multiply by 90: Multiply by 9 (as above) and put a zero on the right.
Multiply by 98: Multiply by 100 and subtract twice the original number.
Multiply by 99: Multiply by 100 and subtract the original number.

Bonus: Percentages

Yanni in comment 23 gave an excellent tip for working out percentages, so I have taken the liberty of duplicating it here:

Find 7 % of 300. Sound Difficult?

Percents: First of all you need to understand the word “Percent.” The first part is PER , as in 10 tricks per listverse page. PER = FOR EACH. The second part of the word is CENT, as in 100. Like Century = 100 years. 100 CENTS in 1 dollar… etc. Ok… so PERCENT = For Each 100.

So, it follows that 7 PERCENT of 100, is 7. (7 for each hundred, of only 1 hundred).
8 % of 100 = 8. 35.73% of 100 = 35.73
But how is that useful??

Back to the 7% of 300 question. 7% of the first hundred is 7. 7% of 2nd hundred is also 7, and yep, 7% of the 3rd hundred is also 7. So 7+7+7 = 21.

If 8 % of 100 is 8, it follows that 8% of 50 is half of 8 , or 4.

Break down every number that’s asked into questions of 100, if the number is less then 100, then move the decimal point accordingly.

EXAMPLES:
8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5

Also it’s usefull to know that you can always flip percents, like 3% of 100 is the same as 100% of 3.

35% of 8 is the same as 8% of 35.

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• tony3s

I didn't know about trick number 10.
And it seems there is a good reason for that, because it doesn't work !

e.g.: 58 / 9 = 6r4

but according to the trick: 5r4

e.g.: 587 / 9 = 65r2

but according to the trick: 54r2

So this trick doesn't work all the time.

The only thing that's true is that summing all the numbers gives the remainder (I knew that).

But good post to remind people math doesn't have to be hard. :)

• Graeme

for starters you need to learn to read, trick number 10 = 10. Assorted Multiplication Rules

as far as i can remember 58 / 9 = division?

• fahim

but here no trick is about 10 tell me which one?

• blazak

The trick for multiplying by 9 is good, but I always thought you'd look like an idiot in math class staring at your fingers, so my trick was simply…the answer will add up to 9, with the first digit being one less than your original multiplier…

ex – 7*9 = 63 (6 is one less than 7, and 6+3=9)

• anjani

11*9=? by trick

• ishan jain

11* 10= 11o then subtract the orginal multiplier 11

110 – 11 = 99

• mathemagician

since 11 and 9 has 10 in middle.
11 * 9 = square of 10 – 1= 100 – 1 =99.

• Onela ;)

Is there an Easy Way to Do Percentages.. Like Breaking it up or Something? I am Pretty Bad at it.! :D

• aman

11*9=(11*10)-11+110-11=99

• Todd

Also, a trick for the nines are the results (up to 9×9) will add up to 9.

2×9 = 18 = 1+8 = 9
3×9 = 27 = 2+7 = 9
4×9 = 36 = 3+6 = 9

I learned that off 321 contact as a small child and never forgot it.

• tinkerbell

it works for every multiple of 9, except 99

• Sam

It does work for 99. 9 9=18, 1 8=9!

• Ria Verma

11*9=99
by trick
put the same number of zero like 9 after the number to which we have to multiply by 9.
i.e for 9 put 0, for 99 put 00, for 999 put 000 and so on.
then subtract the number which is going to be multiplied by 9.

110-11= 99.

comment on it.

• SONU

THIS POST IS WRONG ONE . U JUST MULTIPLY 11 BY 99 BY THIS RULE, THE ANS VILL B WRONG

• vicky

11*9= 11*09= 0(0+9)9= 099=99
what do u say

• Jo-Anne

Here’s a trick learned for multiplying by 9’s.

9 x 1 = 9
9 x 2 = 18
9 x 3 = 27
9 x 4 = 36

If you notice the first digit goes up by one and the second digit goes down by one. When you get into the hundreds the first two numbers will go up by one and the last number will continue to go down by one.

• Lenin Anand

for 8 it is
8*1 = 08
8*2 = 16 (i.e and one to the left and subtract 2 in the left)
8*3 = 24
8*4 = 32

• shonak

09*11
0_9
0(0+9)9
99

• Onela ;)

The easy way to do that is you should remember 11*9= 99 and then 12*9 is 108.. All you had to do is add one to the first number and Subtract One from the Second Number.. If you add 1 to 9 its 10 and if you Subtract 1 from 9 it’s 8.. So then you put that together it makes 108.. Same wise for 13 you add one to 10 which is 11 and subtract 1 from 8 which is 7 and so the Answer is 117.. Easy.

• SONU

THIS METHOD WILL BREAKS BETWEEN EVERY TENS IN TWO DIGIT NUMBERS AND ALSO VARY FROM THREE DIGIT NUMBERS. I.e UR METHOD IS APPLICABLE ONLY FOR FEW NUMBERS

• Onela :)

Yeah that’s Right..! I am Sorry..! :(

• vibha

how 12*9= ? by trick

• Sarah….

The trick for that is you should remember 11*9=99 and then to find 10 you add one to the first number and subtract one from the second number.. So 9+1=10 which is the fist number and 9-1= 8 which is the Second number.. Therefore the answer is 108.. Same wise for 9*13 Add 1 to 10 and Subtract 1 from 8 so the answer is 117.. EASY. :)

• Reea

I always sucked at math, this is useful, another interesting list, love your site!

• Reea: same here – this list stems from my trying to find something to help me fix my mess of a mathematical brain.

• tony3s: You are right – I have replaced 10 with assorted multiplication rules because the previous number 10 does only work in certain circumstances.

awesome list. i inadvertently learned some of the tricks listed here. but i used to memorize math…

• Strath

Oh, and #1, simpler method to multiply by 11 and it works for any number of digits.

Multiply by 10 and add the original number.

• ryan

thanks that helped me alot

• One trick I use that I didn't see listed is multiplying large numbers.

Like:

12 x 734

can be broken into ((10×700) + (2×700) + (10×34) + (2×34)) = 7068

or

8 x 6846

can be broken into ((8×6000) + (8×800) + (8×40) + (8×6)) = 54768

basically you break the number into tens, hundreds, thousands, etc and mulitply each group. with some larger numbers it can get hard to remember each "sub-number" but if you're trying to estimate, its a good way to get a rough idea.

great post otherwise, i learned a lot of tips i wouldn't have thought of otherwise..

~ow3n

• Ria Verma

can you solve it by tricks? i need the proper solution.
what will be the reminder of (25^25)/26?

• Just a teenage boy

Remainder 1

• Sidhant

734*12 is 8808 -_-

• To multiply something by five, I always multiplied by ten, then halved the answer.

• ganesh

Nice one

• yatayuauiaoia

Hi this anser is 12264ed654f f5f4 f548f745df4d8f7 f48fd4f 5f4df f1 ff4e8r1f f54f4f f4f45 4 5f4 5 4 5fefwf fff

• Dan

I prefer calculators… but I do know a few of these tricks and they are helpful when I don’t have one.

• My brain freezes when numbers and words are combined.

I know most of these things, I can do them without thinking. But, when I read how to do them, I just zone out.

It just seems too confusing, like trying to translate English into Chinese characters using pinyin.

Math has its own language.

#3… 2682 / 2 = 1341 (even number so add 0) …

Isn’t 1341 an odd number? the math still works, but I’m all sorts of confused now. And I’ve always sucked at math

• It's WHOLE NUMBERS vs. FRACTIONAL NUMBERS, not Odd vs. Even.

(Maybe it has been updated since your comment.)

• Neat stuff, but #3 appears to be incorrect.

It says if you have an even number, you add a zero to the end and if you have an odd number you add a 5 to the end.

I believe they mean to say, “if you have a WHOLE number add a zero to the end, and if you have a fraction/decimal then add a 5 to the end.”

1341 is an ODD number, not an even number. But it IS a WHOLE number.

• shad and Tom: thanks – corrected.

• Strath

#3 is just the reverse of #8. Divide by 2 and shift the decimal place. No need to remember even/odd whole/fractional rule.

2682 * 5

Step1: 2682 / 2 = 1341
Step2: Move the decimal: 13410

5887 * 5

Step1: 5887 / 2 = 2943.5
Step2: Move the decimal: 29435

• Strath: thanks for the additions :)

• Some cool tricks here, heres another, to find if a number is a multiple of 3, add all the numbers together and if they are evenly divisable by 3 then it is. e.g: 9576 –> 9 + 5 + 7 + 6 = 27 therefore 9576 is a multiple of 3

• We teach many of these "tricks" in our Mathnasium Learning Center (www.mathnasium.com). Sorry for the plug, but here are some interesting "tricks."

Find 7 % of 300. Sound Difficult?

Percents: First of all you need to understand the word "Percent." The first part is PER , as in 10 tricks per listverse page. PER = FOR EACH. The second part of the word is CENT, as in 100. Like Century = 100 years. 100 CENTS in 1 dollar… etc. Ok… so PERCENT = For Each 100.

So, it follows that 7 PERCENT of 100, is 7. (7 for each hundred, of only 1 hundred).
8 % of 100 = 8. 35.73% of 100 = 35.73
But how is that useful??

Back to the 7% of 300 question. 7% of the first hundred is 7. 7% of 2nd hundred is also 7, and yep, 7% of the 3rd hundred is also 7. So 7+7+7 = 21.

If 8 % of 100 is 8, it follows that 8% of 50 is half of 8 , or 4.

Break down every number that's asked into questions of 100, if the number is less then 100, then move the decimal point accordingly.

EXAMPLES:
8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5

Also it's usefull to know that you can always flip percents, like 3% of 100 is the same as 100 %of 3.

35% of 8 is the same as 8% of 35.

• You say "35% of 8 is the same as 8% of 35."

That's because Multiplication is Associative, meaning that the ORDER
in which you group the items to be multiplied is wholly irrelevant.

(0.35 times 8) is the same as (35 times 0.08)

So saying that 35% of 8 is the same as 8% of 35 is simply
"associating" the .01 (the decimal equivalent of 1%) first with
the 35 and then alternatively, with the 8.

Premise:
( 35 percent ) * 8 = 35 * ( 8 percent )

Proof:
( 35 * 0.01 ) * 8 = 35 * ( 0.01 * 8 )

Moot point: The above equation is equal to [ ( 8 * 35) * 0.01 ]

• This Space Intentionally Left Blank

For and equation like 35% * 8

I would break this down to simplify

= 35% * 8
= 35 / 100 * 4 * 2
= 35 / 100 * 2 * 2 * 2
= 35 * 2 * 2 * 2 /100
= 70 * 2 * 2 /100
=140 * 2 / 100
=280 /100
=2.8

If you break it down you should be able to do it in your head

• WEird

This trick is useful for students who freeze when seeing “complex” percentage questions:

E.g.: 27% of 150 <– class went blank
150% of 27 <– which is 1.5 * 27, most of the class got it right

• ben

I wish I would have had this a few years ago! Now im in high school calculus, its a little harder than these rules apply :( still great!

• 1, 2 and 3 I knew about (you can excercise them with the following feed –http://www.mental-workout.com/)

about 1 : I also worked out you can do the same with 3 numbers eg.

172 * 11

1(1+7)(7+2)2 = 1892

I am pretty sure you will be able expand on that even further.

5 and 6 did seem obvious to me.

9 I would rather go to the nearest 100 eg. 1000 – 700 = 300 and then do an easy 100 subtraction 100 – 48 = 52 then add them up 300 +52 = 352 (may seem longer but actually goes pretty fast in my mind)

Thanks for the others

• Dhammika

Your system is very nice. But if u get 182*11 what will be the system for calculation. pls tell me.

• I do it a bitdifferently…

1 8 2
+ 1 8 2

It's what they taught us is Grade School… using zero as a place holder…

10 x 182 = 1 8 2 (0)
+ (1 x 182) = 1 8 2
——————
2 0 0 2

• First of all i would like to thank to Andre du Plessis who has wonderful trick. Well if you go for 182 * 11 = It will work like this:

1{(1+8)}{(8+2)}2 = Now start adding from right side

1{(1+8)}{(10)}2 = But we will keep only 0 with us and 1 will be added in left side value

=> 1{(1+8+1)}02

=> 1(10)02 = Again we will keep only 0 with us and 1 will be added with left side value

=> (1+1)002

=> 2002 = Will be the answer

I used this trick many times and it is really working. However, But I felt that I can make faster a multiplication for any no. with 11 as its table is very easy :)

• raj

instead of tht ll tell u a better method…..
182*11= 18(18+2)2
18(20)2
18(2,0)2
20 & remainin number 02
ans s 2002

• hafiz asif

e.g: 123*11 = 1353
write 1 as it is
then write 5 as it is

• josef

my system would be definitely 182*10=1820+182
and thats the way i make everything easier i use almost always the numbers
10,2,5 to make my math easy.

• umesh

ur method is great and useful to anyone . thank u very much. if u have other short-cut tricks of math please send me

• Fe

Gotta agree with China Tattler, trying to read how to perform math tricks is like trying to sing a fragrance, it just doesn’t work for me. I worked in a fabric store for four years and pretty quick picked up all sorts of tricks to calculate percentages, discounts, fractions and decimals all in my head, but explaining them confuses just about everyone.

• Ben

Here is a trick…

I turn on the calculator and start typing!

JK

These are great tricks essp for the kids still in high school and middle school. The joys of college math is the same but you dont use numbers just english and greek letters.

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• penny

A better system:
The Tractenberg System Of Speed Math.
Also check out:
For advanced tricks–such as superspeed Langrange
Division.

• Yanni: That is the most useful mathematics tip I have ever heard. Thanks for adding it – brilliant!

• Robert

I always liked the trick to determine if an integer is divisible by 3 – just add up all the digits in the number, and it those digits are divisible by 3, the original number is divisible by 3. 114 = 1+1+4 = 6 – 114 is divisible by 3.

• rambo

we know yaar!!!!

• this is amazing ! i only knew few of these tricks

thanks for sharing ^^

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• Another approach is the “is x divisable by y?”-question:

A number is divisable by 2 if it’s an even number.
3: The sum of the individual digits is divisable by 3, e.g. 174 => 1+7+4 = 12 (=> 1+2 = 3)
4: The last two digits is divisable by 4
5: The last digit is 5 or 0
6: The number is divisable by 2 and 3
7: Double the last digit and subtract it from the rest. If the result is divisable by 7, the original number also is. E.g. 483 => 48-(3*2) = 42, divisable by 7
8: The last three digits is divisable by 8
9: The sum of digits is 9
10: The last digit is 0
11: Subtract the sum of “even” digits from the sum of “odd” digits – if divisable by 11 (incl 0), the original number is divisable by 11: E.g. 7084 => (7+8)-(0+4)=11. 7084 is divisable by 11.

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• Here's a quick tip to multiply any two numbers that are between 11-19 (like 13 * 15):

1. Take the first number (13) and multiply by 10

(13*10)=130

2. Take the last digit of the second number (5) and multiply by 10

5*10=50

3. Add the results of steps 1 and 2

130+50=180

4. Get the last digit of the first number (3) and the last digit of the second number (5) and mutiply the two

3*5=15

5. Add the results of step 3 and 4

180+15=195

Try it. It sounds complicated but once you remember it, it gets useful

For the same there is one easy method:-
(13*15)=?
2. Multiply (3*5)=15 i.e. 5 with carry 1
3. Put the both result:- 18 and 5 with carry 1, carry will be add in 18
=195 (19=18+1)
M.Sc., M.Phil. India, [email protected]

• MAHU

1/25+1/20=?

• Skaz

9/100 ?
;-)

• Nagaraj Hanchinal

this is the base “10” method
this is very easy to remember
and we can do this trick with 23*21 also
but take here base as 20,
here, 21 is one more than 20
then double up 24=24*2=48 (because the base 20 is 2 times the base 10)
still we need one digit because the base 20 has one “0”
so, 3*1=3
i.e, 23*21=483

• Pankaj

if we do it with this method then it will be very easiy.13*15=14*14-1=195

• NOOB

You are god.

• Check out MathMojo.com for other tricks and tips. There is a link to a good, interactive lesson on multplication by 11 and 12 for huge numbers on the homepage.

• frogandpig

I have always figured out how much a certain percent is by using either 1% or 10%, then easy basic math.
Example:

4% of 430 = ?
1% of 430 = 4.3
4.3 x 4 = 17.2
or
(4×4)+(.3×4)=16+1.2=17.2

15% of 58 = ?

10% of 58 = 5.8
5% of 58 = 5.8/2 = 2.9
15% of 58 = 5.8 + 2.9 = 8.7

or 10% = 5.8 and 1% = .58
.58 x 5 = (.60 x 5) – .1 = 2.9

Rounding works great for tips at restaurants

15% of \$58 = ?
15% of \$60 = 10%(\$6) + 5%(\$3) = \$9

And if you round but still want the exact amount, subtract the percent you’re trying to find from the additional amount you rounded. (Works easier for large numbers, but the concept is the same.)

60 – 58 = 2
15% of 2 = .3
9 – .3 = 8.7

Decimal places are moved easily in my mind, so maybe this trick only works for me?

• keisha

Thanx but these top ten arithmatic tricks did’nt really help me as i got confused half way through a couple of them so if i was you i would make it easier to UNDERSTAND!

• sverrirp

Trick number two doesn't work out:

35*35 = (2x(3+1)) & 25

2 x 4 = 8 = 825 according to the trick

But 35*35 = 1225

You need to read the trick better. MULTIPLY THE FIRST NUMBER BY ITSELF PLUS ONE.

35*35 = (3X(3=1)) & 25

3×4 = 12 & 25

1225.

• arvind

lol its 3x(3+1) not 2x(3+1)

• anju

its like 3(3+1)& 25
3(4) & 25
1225

• sumit

its 35*35 for tthat (3*(3+1)) & 5*5
12 & 25
1225

• Monojit Paul

The original trick is_
35*35 = { 3x (3+1) } & 25

3 x 4 = 1225

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• imajoebob

Why didn’t you follow your own tax tip rules for multiplying by 15?

Instead of multiplying the first factor by 10, and then the second by 5, which some people may find difficult, just multiply by 10 (i.e. add a zero) then divide by 2 and add it to itself.

237 x 15 =
(237×10) + (237*10)/5 =
2370 + 1185 = 3555

Or you can always multiply by 100 and use your 15% tax formula.

• Tom H

A better tip for multiplying by 6: multiply by 5 (as stated) and then add the original number.

I find this easier than multiplying by 3 then 2…

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• achan

Found this neat trick about the 11 rule – expanded.
What is 51236 X 11.
First step, 051236
Second step, 5(5+1)(1+2)(2+3)(3+6)6
Found it here

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• Ace

Awesome tips guys! Also.. Monsolo, I like yours too. Thanks!

• Jim C.

To convert between ounces and pounds, divide or multiply (as required) by 2 four times.

The same applies for price per ounce and price per pound.

• @sverrip

Trick 2 is correct:

35*35 = 3 x (3+1) & 25 = 12 & 25 = 1225
45*45 = 4 x (4+1) & 25 = 20 & 25 = 2025
55*55 = 5 x 6 & 25 = 30 & 25 = 3025

• onikirol

even numbers multiplied by 6:

6×2= 12
6×4= 24
6×6= 36
6×8= 48

the even number is placed as the 2nd digit, and half of it is placed as the first. (the first step always applies, but the 2nd step is only true for 2, 4, 6, and 8 )

and for multiples of 5, I’m like Miss Cellania in that I go for multiply by 10 and then half it

• MikeB

You might want to look at this book: “The Trachtenberg Speed System of Basic Mathematics” which explains for example how to multiply two large numbers without the need for calculator or paper.

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• imajoebob: you are correct, but I wanted to mention as many options as possible because of the very reason you state – some people find different methods easier – two methods are better than one :)

Thanks guys for the extra tips – they are all really useful and make for an excellent resource.

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• Fantastic list. I use a fair few of these already, but have certainly learnt a few more. Trick 9 applies to 10 to the power of any number – 10, 100, 1000, 10000 etc too.

• Colin Seymour: thanks :) I am glad it will be of use to you – thanks also for expanding on trick 9. These comments are as useful as the list :)

• Actually, Rule Number 3 (Multiply by 5) is a complicated form, of explaining what already is said in in First Item in Rule Number 10 (Multiply by 5: Multiply by 10 and divide by 2)

And this is very simple to understand because, 10/2 = 5

so,

2682 x 5 = 2682 x (10/2) = 26820 / 2 = 13410

or if you prefer to halve first
2682 x (10/2) = (2682/2) * 10 = 1341 * 10 = 13410

No weird rules for 0 or 5 just plain multiplication and halving :P

Remember that multiply by 10 in decimal (base 10 system) is easy, just add 0 to the right.

And halving something is second nature to any one which had a brother :)

• portnoy

Of course any even number is divisible by two but,

If the last two digits of a number are divisible by 4 then the whole number is divisible by 4.
If the last three digits are divisible by 8 then the whole number is divisible by 8…. etc.

The rules about 3 apply to 6 and 9 too.
If the digits add up to be a multiple of 3 and the number is even then it's divisible by 6.
If the digits add up to be a multiple of 9 then it's divisible by 9.

Seven is the only goofball.

"If the digits add up to be a multiple of 9 then it's divisible by 9"

Uh… Isn't any number that is a Multiple of X, also divisible by X?

That is like saying that any number that is a multiple of 5, is also divisible by 5.

Kind of obvious?

• Jay

He's talking about cases where the individual digits ADD UP to a multiple of nine. 3+3+3=9; 333/9=37

• sabitri baral

to get square of numbers like 05,25,35,45,55,65,75,85&95 upto 100 at first multiply the second number by 5 and multiply the first number by adding one on it. for eg:25^2=5*5=25 and put it on second like:_25 and multiply 2 of 25^2 with adding 1 on it.At last multiply 2 with 3 in which you got 3 from adding 1 on 2.then put like this:_25=3*2=625
eg: 25^2=5*5=_25
and
2*(2+1)
=2*3
=6 and put on second
=625

• This is great, I suck at math so this is very handy!!

• Woody

One trick I learned thats useful is how to do square roots when you don’t have a calculator handy. It’s simple and works quite nicely as follows:

Subtract successive odd numbers, starting at 1, until your remainder is less than the next odd number.
Count the number of odds you subtracted, thats your whole part, then put the next put your remaining value over the next odd to get your fractional part.

The fractional part isn’t exact, but it’s usually close for large numbers.

For example:

9 -1 = 8 -3 = 5 -5 = 0
1 2 3

So the square of 9 = 3 (count of 1,3,5)

You can also use addition to get there as well:

120 = (1+3+5+7+9+11+13+15+17+19)+20
1 2 3 4 5 6 7 8 9 10 remainder

So, the square of 120 is 10 and 20/21 (10.9523)
The square of 120 is actually 10.9544, but 20/21 is pretty close and easier to work with if you’re not using a calculator.

If you have a rough idea of where its at, you can also figure out a quick “jump in” by guessing close. The close value can be multiplied by 2, and added to 1 to get the next odd in the sequence. For example, lets do 10535:

For 10535 we know 100^2 is 10000.
(100 * 2)+1 = 201, the next odd to use.
535 – 201= 334 -203 = 131
So Sqtr(10535) ~= 102 and 131/205 (.639 vs .640)

Hope this is helpful to someone!

• I am amazed at how mathematical our users are here! Well done.

Oh – and hi to everyone coming from lifehack.org – thanks for visiting and contributing to the comments!

• Logi Helgu
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• swimner

Relations of square numbers

We can get 15^2 = 225
13^2 = 15^2 – (15+13)(15-13) = 225 – 28*2 = 169
17^2 = 15^2 – (15+17)(15-17) = 225 -(-64) = 225 + 64 = 289

Twisting the trick a bit, we can generate ALL Pythagorean Triplets

Most people will recall a 3,4,5 triangle
Some remember the 5,12,13 triangle
Few remember the 7,24,25 triangle
Most don’t know the 121,7320,7321 triangle

Note that the smallest side is odd.

Simply square an odd number such as 9^2 = 81
Divide in half (not evenly)
An uneven split of 81 is 40,41

So 9,40,41 is a pythagorean triplet

ie 9^2 + 40^2 = 41^2

It also works for even numbers, but they have to have at least one odd factor.

Lets try 10. Find the pythagorean triplet for 5.
5,12,13 and then muliply by the other factor of 10 (namely 2) to get 10,24,26.

For powers of 2 we must be really sneaky.
Take 2^6 = 64.
Divide the number by 4 to get 16.

We know 3,4,5 is a pythagorean triplet.

Multiply the triplet by 16 to get 48,64,80.

We owe this to the Babyloneans (3000+ years old).

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• That pretty excellent and good!! I am really impressed with the way you have come up with the math..I will surely use this technique…

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• For restaurant tips I usually just double the sales tax, which here is about 7.5% — yielding 15%. If yours is a bit lower or higher, just round up or down a little bit to get it close enough.

• Nazzyon

I am good @ Maths but my problem is speed/time.

Now I will be able to solve faster than usual. My B’s will definitely fire up to A’s if I make use of these tricks.

Thanks for contributing

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• you people are scary!!

• pallav: but they will be earning the big bucks one day (if not already!) Nerds rule :)

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• its soooooo amazing

• sahil

its simply superb!!!!!!!!!!!

• flower

Fear of Maths is only mental.I suggest:
1.Instead of saying DIVIDE BY 2, say HALF/HALVE IT.
2.Instead of saying MULTIPLY it by 2, say DOUBLE IT.
3.Never use more than two digit numbers to prove the working of a method.
4.Show the more interesting sides of maths, for example,show the beauty of the table of nine (which really looks cute, simple and well arranged).
After these small things, leave the person to grow up inside herself, by herself. They’ll start with small victories, and keep gathering courage for bigger ones. Maths IS easy and beautiful upto a certain level. Let’s all enjoy this beautiful, universal language.

• wellwisher

I really liked your thought, but this will not help to solve tough problems……..

• HI!
Isnt all this High Speed Vedic Mental Mathematics from India?
Vedic Math is the world’s fastest mental math method from India- You can do calculations much much faster compared to the normal method or even a calculator.
Check out this site on Vedic Maths which has lots of tutorials and resources.

The tutorials given here on Vedic Maths are the best. Do Check them out.

Hope it helps!
:)
Gaurav Tekriwal
http://www.vedicmathsindia.org

• wellwisher

Thank you for the suggestion I'll try that………..

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• Catdancer

Good to know these things! I’m an elementary teacher and have used a few of these before but not all. As for the finger trick when multiplying by 9, I teach that every year. It’s great for elementary age kids and some higher grades, too.
I have a trick for calculating a tip that doesn’t involve anything tricky. I figure out what 10% of the bill is by moving a decimal point, then I add the amount of the sales tax to the 10% figure. My state has a 6% sales tax so it works well for me. If you had 8%, you could just double the amount of the tax. I never worry about an extra 1% for the tip – that’s usually just a few pennies.

• Gaurav Tekriwal – thanks for the additional information – I am sure many people will find it useful.

• rachit

its trully amazin.

• Catdancer: great idea about the tip – thanks for mentioning it :)

• jackR

OK, all interesting tips but to me it’s easier to just do the math than to try to remember all these. Now, if there’s one or two that you find you use regularly that’s fine.

• when multiplying two numbers that differ the same amount from a multiple of 10 (for example, 39 and 41, or 25 and 35), you can just square that multiple of 10 and subtract the square of the difference.

27×33
=30^2- 3^2
= 900-9
=891

(works due to difference of squares)
(30-3)(30+3)

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• Here’s a quick method I made up was I was younger for squaring any size of number (I mostly use it for 2 digit numbers though), and it’s far handier than Trick #2 of this list.

It’s adapted from the perfect square identity (a+b)^2 = (a^2 + 2ab + b^2) [which I didn’t make up myself, lol].

73^2
=(70 + 3)^2
=70^2 + 2 * 70 * 3 + 3^2 #70^2 is 7^2 * 10^2
=4900 + 420 + 9
=5329, which is right.

Or,

44^2
=(40 + 4)^2
=40^2 + 2 * 40 * 4 + 4^2
=1600 + 320 + 16
=1936, correct again.

For cubing or quarting or whatever higher powers, you could prbably do a binomial expansion on it, although that would probably take a far longer time, unless you’d memorised the binomial coefficients( rather than calculating those factorials each time).

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• >> 3. Multiply by 5
What just not to multiply by ten, then divide by two? So you won’t need to check for a reminder.

• Renessaince – it is good to have a variety of ways to do the same thing as we all think differently from each other.

Thanks for the additions Lisa and Stuart.

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• Richard

Square numbers with 1
Example 11^2 or 111^2 or 1111^2

1st Count the digits
2nd Start writing 1,2,3… up to the Counted digits and then go back!

e.g. 1111^2 – It has 4 digits
then we have 1,234,321

With 11 -> 111^2 it has 3 digits
then we have 12,321 – count up to 3 (1,2,3) and then go back (2,1) : 12321 =>(12,321)

That’s all Folks
“Viva Chavez”

• John

Hey this is a great list. I already knew most of them because math was my favorite class in high school. Although, I did number 1 differently. It’s a much easier way and it works no matter how many digits your multiplying by 11. What you do is take the number you’re multiplying by 11 and write it down. Then you write the same number below it but shift the numbers to the right one digit. Then all you have to do is add them together. This would be the same as multiplying by 10 then adding one because the first number has one more digit than the one below. This process just always seemed to work better in my head.

45287 x 11 = ?

45287
+45287
498157

• Have you heard of the Russian Multiplication method. It’s quite fun and you can multiply any two two-or-more-digit numbers together using this method. Not sure if it is easier than the traditional algorithm (method) but it is fun.

1. Write the two number down on a line – write the smaller one first.

2. You will form two columns of numbers.

3. First column – halve the number in the first column write down the answer ignoring the remainder (or fraction). Write down until the first column is reduced to 1.

4. Second Column – double the number in the second column and write down the answers – keep doubling until you come parallel to the 1 of the first column.

5. Go down the list of numbers in the first column and draw a line through or delete the even numbers and their adjacent numbers in the
second column.

6. Add all the remaining numbers in the second column.
Voilá.

Example: 45 x 87 =

45 87
22 deleted 174
11 348
5 696
2 deleted 1392
1 2784

Numbers deleted from columns 22 & 2.
So 45 x 87 = 87 + 348 + 696 + 2784
= 3915

I have tested this on numerous occasions and it has never failed. Two reasons why this is easier than “long multiplication” –
1) Halving and doubling is quite easy mental arithmetic.
2) Addition is easier than multiplication.

I have done the proof to find out why it works.

• aplspud

Math scares me.

• densom

awesome!!!
It is very helpful to me specially I’m majoring in mathematics.

• Hi,

Nice list. I’ve got a similar one, with a few differences, on my blog, http://wildaboutmath.com. I’ve also got an article on a simpler way to square numbers.

all bodies nice work, i have a better way for squring two digits, and more abt multiplication,

• I would like to see a continuation of the topic

• My blog now has a few videos about Math tricks. See http://wildaboutmath.com/videos and I’ll be doing more over time, especially about the Vedic techniques, that are not well covered in many other sources.

• check

How to check if a number is divisible by three:
add separate numbers together and if they are divisible, the entire large number is.

Like for instance 1234: 1+2+3+4=10 – is not divisible.
1233: 1+2+3+6=12 – is.

• check

sorry, last one was meant to be 1236, but both examples are good.

• Wendy

I am having trouble with a quick way to figure out this example:

12.5% of 5416

• Dear Wendy,

I am not sure why you are asking for the quick way, but I will not be facetious and say “use a calculator. As a teacher, I would remind children that percentages are just another way of doing a fraction.

It would helpful to have a few standard percentages in mind…

10% = one tenth (divide by ten)
20% = one fifth
25% = one quarter (or fourth depending on which side of the atlantic you dwell)
etc.
12.5% = one eighth

So I divide 8 into 5416.
Is the same as dividing it into
4800 (600)
and 600 (75)
and 16 (2)

Total 677.

Note of Caution: Children must understand the concept of fractions and percentages, and only if they get that link can you suggest this method.

Most Children know that 25% is 1/4 and you can ask what is half of 1/4 (be careful some children might this it is 1/2 because they halve the denominator.) When they have 1/8 then ask what is half of 25 – wait while the work it out, and then say if half of 1/4 is 1/8, and half of 25% is 12.5% then 1/8 is the same as 12.5%

The key is that they can relate common fractions to percentages and visa-versa.

I hope this helps you – I hope you don’t think I am talking down to you.

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• Eric B.

Whilst these math helps are valid ways of making calculations, in the real world one is not often presented with “pre-made” problems, such as:

1. you need to multiply a number by 11

2. you need to square a 2 digit number ending in
5

3. you need to multiply any two numbers that are between 11-19

4. you need to multiply two numbers that differ the same amount from a multiple of 10

These problems are so far-fetched from those encountered by citizens engaged in common jobs relating to commerce, accounting, engineering, administration, clerks, etc.

I don’t see any benefit from the mastery of these very narrow skills except for math contests, which are like spelling bees.

Sure, the winners can spell all those words and the math winners can calculate some obscure problem in a short amount of time, but I ask, in concrete terms, how those abstract math skills translate into stepping into a job:

* cashier
* machinist
* factory worker
* stock worker
* truck driver

• John F.

You make a good point Erik B. about the “usefulness” of knowing these tricks – and indeed, they are novelties – a bit like a clever card trick – amazing to watch being performed, and fun to do, but really not practical on a day-to-day basis.

However, as a maths teacher, these “card tricks” do have some use, in building a student’s confidence in his/her ability to do maths. Confidence is a very important ingredient in the “learning recipe.” The other aspect is, fun. Sadly, maths is too often NOT regarded as fun. On the contrary, it strikes fear into the hearts of young students. By highlighting the “fun” factor, we hope to coax and lure students into this mysterious world called “Maths” so that they gradually become familiar with the cities called addition, subtraction, multiplication and division. They recognise fractions in their multifarious guises, and begin to see how, in fact, they were in the world of mathematics all along (problem solving).

One can, I suppose have an “essentials only” philosophy of life, but personally, I think spelling bees and maths olympiads add a certain spice to life. Can you imagine a world with no baseball, basketball, football or hockey? Imagine never being able to go to the theatre to watch a play, an opera or a dance? What if there were no circuses? I think you get my point – many of these “tricks” are just for fun – but so what?

• The very first rule in being a good foreman on a construction job is to surround yourself with lots of talent. The second rule is that when being confronted with a hard task, let someone else do it. Even math. Good tips and I love them.

• pidro

your Math tricks ma help me to work fast and accurate even in our algebra problems. In my 1st time to see this,I told my classmates about this. then, I see now the easy way to solve mathematical problems.

• pidro

This is easy… I can now solve basic math problems using this techniques… :)

• sandeep

• Alan

What a great lot of tips and tricks – thanks. Sevenths are wonderful things too. They are recurring decimals – they never end. So 1/7 is 0.142857142857142857…. – i.e. 0.142857 all recurring. 2/7 is the same group of numbers in the same order but starting with the next largest – 0.285714 all recurring. 3/7 is again the same group of numbers in the same order but starting with the third largest number – you guessed it – 0.428571 all recurring. The pattern follows for the rest of the sevenths as well – 4/7 = 0.571428 all recurring, 5/7 = 0.714285 all recurring and 6/7 = 0.857142 all recurring. And of course the number sequence is easy to remember – 1/7 = 0.(7×2)(7x2x2)(7x2x2+1) = 0.(14)(28)(56+1) = 0.142857 all recurring. Ain’t maths beautiful!

You can also multiply 2 numbers together by simply squaring the average of the 2 numbers and subtracting the square of the difference between a number and the average. E.g. to multiply 58×62 you can find the average (60) square that (60×60=3600) and subtract (60-58)squared – 2 squared = 4. Therefore 58×62 is 3600-4 = 3596. Another – 36×44=(40×40)-(4×4)= 1600-16 = 1584. Obviously this works most easily when the numbers are equidistant each side of a number that is easily squared. But it still works for harder ones, e.g. 27×32 = 29.5×29.5-2.5×2.5 = 870.25-6.25 = 864.

• moises of philippines

being a math addict is one of the characteristics of being unique… we should love math

• john fox

nine times table the easy way all the answers add to nine eg.
9*1=9
9*2=18
9*3=27
9*4=36
works to ten

• Blest

This article kicks ass. Thank you so much for writing/publishing it. I really have not had much trouble with math, but many of these “tricks” I did not know. lol. Thank you.

And in terms of the percent”trick”, the other thing that you can do, which I find even easier, is multiply the first number by the first digit of the next number. For example:
8% of 300=21 (8 x 3)
12% of 800=96 (12 x 8)

Again, thank you. Math has always been an enjoyment of mine, and until recently, I had kind of forgotten about it, although still utilizing it for simple calculations. Due to a movie that I saw recently (A Beautiful Mind) and this artcile, I feel a growing fascination within me of reaquainting myself with math and further developing my knowledge and intellect-hungry mind.

• John F.

Yeah that works – but just watch your calculation – 3 x 8 = 24 not 21.

I would suggest that someone useing “Blests” method round of the bigger number to the nearest 100 or, where the number is within 19 of the 50 – eg. 31 – 69 round off to the lower hundred and add a half – e.g. 761 would be rounded off to
7 1/2 and then to find 30% of that would be about 225 – the actual result is 228.3 but it is close enough for estimation.

As I always say, when teaching children make sure they understand WHY the trick works and not merely the mechanics of the trick.

• John F.

Some might argue that I have povided too great a margin for the 1/2 values in the example above. I simply thought it would be easier if you take all the 30’s (except thirt itself, and up to all the 60’s.) rather than quibble about which point the estimation should shift from one to the other. strickly speaking, I suppose it should be the middle third of numbers between each hundred – i.e 34 – 66 but we are talking ESTIMATION here

• ChiBop

One useful tip my dad always told me for figuring out tip is to take the tax and double it. So if the tip is usually 7%, then it brings you up to 14% (slightly less, but helps anyway.)

• sponge dude

Dear robert, I ALREADY KNOW THAT! :-)

• sponge dude

Hi, I just found a LLLLLLLOOOOOONNNNNNNNNGGGGGG way to find squares:

To find the square in this series:

121,144,169,196,_____

Find the square root of the number before that:
196=14
Add the result to the square:
196+14=210
210+14=224=1=225!

Here’s a simpler one:
1,4,___
4=2
4+2=6
6+2=8+1=9

I bet you don’t know that! :-)8)

• sponge dude

8) can you go harder? 8)

squaring two or three digits is sound simple……
we know the formula for
(a + b)^2 = a^2 + 2ab + b^2
consider we want the square of number 47
just replace the digits on the place of variables

Step -I
(4 + 7)^2 = 4^2 + 2(4)(7) + 7^2
Plz ignore + Operaor, i m replacing + operator with a blank space…
(4 7)^2 = 4^2 2(4)(7) 7^2
(4 7)^2 = 16 56 49
Step-II
here is a technical sum
start from right, place first digit i,e 9, and other digit i,4 will be added middle column number , i,e 56. 56+4 =60
…..
(4 7)^2 = 16 56 49
(4 7)^2 = 16 (56 + 4)9
(4 7)^2 = 16 (60) 9
repeating above process with middle number,, similiarly for 60 place 0 same and 6 will be added to the left column
(4 7)^2 = (16 + 6)0 9
(4 7)^2 = 22 0 9
and it is the answer 47^2 = 2209
———————————————-
here are other examples
for example number = 69
formula for square is
(a + b)^2 = a^2 + 2ab + b^2 but remove + operator

(6 9)^2 = 6^2 2(6)(9) 9^2
(6 9)^2 = 36 108 81
(6 9)^2 = 36 (108 + 8)1
(6 9)^2 = 36 116 1
(6 9)^2 = (36 + 11)6 1
(6 9)^2 = 47 6 1
69^2=4761
——————————
for example number is 31
(3 1)^2 = 3^2 2(3)(1) 1^2
(3 1)^2 = 9 6 1
31^2=961
————————-
if u want more….
for squaring three digit number
use (a + b + c)^3
it is also similiar but little trick there.

similiarly for four digit number
use formula of (a + b + c + d)^2
————————————–
OK if you want not square but CUBE of a two digit number then,,
u can use similiarly formula of (a + b^3 ………………..
…………………………………………………………………………
and this never ends ..
U need to A Srong Sum Caculation
and Bionomial Theorem…
if Any Problem Me here…with [email protected]

• Raj

Really this is very usefull for all. Thanks.

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• ??????

?? ? ????? ?? ??, ??????????. ????? ? ????????? ????? ????.

PS: ???? ??, ??? ? ???????, ??, ?????????, ???? ???????? ?? ???????. :-))

• Can someone translate that last comment in to English so I know whether to keep or delete? All I can make out is American on the first line.

• Kreachure

“Well, you stupid Americans. This [is] taught in elementary school.

PS: Despite what I wrote, you probably will not be able to read, too. :-))”

Don’t thank me, thank “GoogleTM Translate”!

• Kreachure

Hmm, that looks too much like I myself was saying it. Oh well…

• riz

Trick number two doesn’t work out:

35*35 = (2x(3+1)) & 25

2 x 4 = 8 = 825 according to the trick

But 35*35 = 1225

Right Tricks:

35*35=1225

(3 x (3+1)) = &25

3 x 4 = 12

ans: 1225

• kiwiboi

riz – huh ? The way you did it correctly is the way Trick 2 tells you how to do it.

Multiply the first digit by itself + 1, and put 25 on the end.

35 x 35

Step One
3 x 4 = 12

Step Two (put 25 on the end)

1225

• carpe_noctem

yeah riz, you just completely made up some random way of doing it and labelled it as incorrect…

• The first one is designed for retards. Just times the number by 10 and add the original number on to the result. If that’s too difficult then you’re also probably having difficulties remembering how to blink.

• kiwiboi

?????? – ?????? ???? ? ????…

• John Morrison

I learn a very good trick for squaring numbers in the 40s and 50s. Think of 50 as 25, and add the ones digit. 51*51 is 25 plus 1. 26, next you square the ones digit. (1 squared is 01, for the answer 2601. Try the next one 52*52 is 2704. 25 plus the 2 is 27, 2 squared is 04.

For the 40s think of 40 as 15, not 16. Add the ones and square the difference between the ones digit and 50. 41*41 is 15 plus 1, 16. The difference between 41 and 50 is 9. Nine squared is 81. Your answer is 1681.

Have fun,
John

• hero

excellent site

• shan

good simple tricks ,good work pal

• John Morrison

• anupriya

I LIKED THE 3RD ONE

• saloni

this was a horrible page!!!!!

• John F.

Please if you haven’t got something to contribute to this discussion in terms of Math tricks and techniques – keep your comments to yourself. Posts such as 113 and 107 are as sad as they are irritating. If you think its a waste of time – fine go elsewhere.

Personally I appreciate the different ideas shared here.

John

• vijay

Unbeleivable but Believable

• kaustubh

1. TAKE 15 & 16 as an example .
2. Remember to place the larger no of the two on top of your mind
3. Then imagine to cover 16 & 5 from a paper mentally . These are the no.s now needed for the whole operation.
5. Place a zero(0) after the last digit to get 210.
6. Multiply the lower covered no. into the single upon it one.(6*5=30)
amazing….!

• kana

Giving Lots of Examples could be useful

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• Nindi

hi, nice rules,
Kaustubh
ur example is difficult i think,
multiplying 16*15 can be done by
Multiply 15*15 by trick
15*15=225
225+15=240
16*15=240
simple

• Vera Lynn

I wanted to do a Math list, but I didn’t think there would be any interest. Guess I was wrong. Good list.

• Tarun

I needed something for the school project o mathematics. The ’11 times trick’ and the ‘tip calculating’ ones have got me into atrraction. I’m sure of scoring a full on full for the project.

Fabulous! Bravo!

• ranu

tricks fails at certain times then how can we use them

• ranu: read the comments – they don’t fail. They all work.

• Pamela

Wow,this was my assignment in Math..good for me to know this website.This one is very helpful for me. Thanks for this!

• Rob

Fantastic ideas im a teacher but terrible at basic maths, this has been a great help

• SAM

MAN THIS IS AWESOME PLZ ADD SOME MORE TRICKS ABOUT HOW TO SOLVE TRANSFORMATIONS PLZZ I WILL BE THANK FULL TO U

• AJAY SINGH SHEKHAWT

HI
THIS SITE IS VERY GOOD
DAILY I HAVE TO OPEN THIS SITE . I HAVE BEEN IMPROVING MY MATHS SHORT TRICKS
PLZ SEND SOME OTHER SHORT TRICKS IN MY YAHOO MAIL
THANXXXXXXXXXXXXX

• SAM & AJAY: YOUR ENTHUSIASM HAS BEEN NOTED.

• https://listverse.com/comment-faq/

think there’s a little something about all caps here.
:)

• Just being smart. :)

• kashish

with the help of this tricks i really got speed in my calculations .
tfe best part of the tricks was how to find the percentage………….

• grt

will anyone tell me the addition trick?

• srinivas

it is better to give simple breif about quantitative apptitude also

• jan marl

hai guyz

• joshua

i sucks at math but when i noticed it,i always recite in math that’s because of this!

• nagendra

can any1 tell me how it is done
this is a 5 digit and 4 line addition. but the next three nos are not displayed but the answer is calculated. plz tell me the steps at [email protected] “NOW REPLY”

eg:-

3 2 3 0 7
– – – – –
– – – – –
– – – – –
– – – – –
————
2 3 2 3 0 5 ANS

How provide the trick how to solve it.
Numbers in the blank are placed upon the above and below lines

• balashubramaniam.m

Any 2 digit number Multiplied by 99……

44*99 = (44-1)(100-44) = 4356
37*99 = (37-1)(100-37) = 3663
78*99 = (78-1)(100-78) = 7722

No multiplication, only addition. amazing… ? .!

M.Bala – [email protected]

• anurag

after reading this i found a easy way to solve problems thanks for that

• smily

or a neat trick for squares of numbers, is…

Problem: find the the square of 51

solution: 50 squared plus two times 51 minus one.
50^2+2(51)-1

• kaus

shit

• Karl

Here goes another one:
multiplying numbers of 2 digits up to 19.
ej: 16*15
take 16+5=21 add a 0: 210
then 5*6=30
and then 210+30=240
Easy?

• pr

nice., i really useful this site to my maths .,

• lowtolerance

here’s a really easy way to calculate a 20% tip, for the non-cheapskates out there:

Double the total and divide it by 10.

Because really, people…15% is the minimum you should tip for good service. Doubling sales tax is certainly easy enough, just don’t do it at the restaurants you like to eat at. Most waiters only make \$2.13 an hour, and they really depend on your generosity.

• vishwam

thanks alot
i came to know a few very useful maths tips
thanks 1ce again
al th best
god bless.

• Aiz22

Thanks a lot for the information. it really helps me a lot. mabuhay web-site nyo!!

• sanjaysingh

tricks for add of odd number in series/43612342513246241443242286541233234242461242

• darkstar8

Squaring 2 or 3 digit numbers Trick:

let the number to be squared be called as the BASE.
let the difference of the BASE from 100 be called as the MAGIC NUMBER.

to square: SUBTRACT the MAGIC NUMBER from the base, then APPEND the square of the base.

examples: BASE MAGIC NUMBER = 100 – 97 = 3
97 – 3 = 94 (makes up the first two digits)
3 x 3 = 09 (makes up the last two digits)
thus, 97 x 97 = 9409.

89 x 89 –> MAGIC NUMBER = 100 – 89 = 11
89 – 11 = 78
11 x 11 = 121
121 is 3-digit, so we add it like this:
78 (the first two digits)
121 (we retain the last two, and add the first)
——
7921 –> 89 x 89

examples: BASE > 100
——————————————————
106 x 106 –> MAGIC NUMBER = 100 – 106 = -6
106 – (-6) is like 106 + 6 = 112
6 x 6 = 36
thus, 106 x 106 = 11236.

This works everytime, and is useful as long as you know the square of the base.

For larger numbers, this trick is also applicable using 1000 as the one we subtract from, however, we are using 3 digits now, so we expect 3 digits from both process:

ex. 989 x 989
1000 – 989 = 11 (magic number)
989 – 11 = 978
11 x 11 = 121
———-
989 x 989 = 978121

ex. 1012 x 1012
1000 – 1012 = -12
1012 – (-12) = 1024
12 x 12 = 144
———–
1012 x 1012 = 1024144.

looking at these makes us feel that we can also do these for numbers near 10,000, using 4-digits from each process:

9994 x 9994 –> 9994 – 6 = 9988
6 x 6 = 0036
———————-
99880036.

Hope this helps.

I’ve just looked a bit in this site and found lots of good stuff. I’m not a great big fan of math, but I find some of it interesting. I hope you all will look through this site when doing your math. Especially kids.

• kavi shah

this website rocks man!

• ameena

we can find out the total before we add it
steps
1.tell the other person( audience) to tell you a 3 digit number and write that number on a paper
2.subtract that number by 2 and put 2 in front of the answer, that will be your total.
3.then tell the audeince to tell an other 3 digit number, write that down on the paper.
5. now tell the audience to tell an other 3 digit number write down the answer
6. sub. by 999 and write down the answer.
7. now tell the audience to total it up and he/she will be suprised

eg.

(a)- audience
(s)- you

415 (a)
725 (a)
274 (s)
398 (a)
601 (s)
——-
2413

• faiz

i have 1 fantastic trick 4 multiplication wth 9

• jp14

there is a trick done with 25 pennies… the object is to get the last penny not the most… you play with a partner and you can take as many as 3 or as little as 1… there is a fool proof way to win everytime see if you can figure it out and post it on your site

• BOUREZZA

merci boucoup

• Yawa

fascinated hehehe hmmm!

• Yawa

Here are the tricks,

Copy them
and paste

Easy!

• 6twistedbiscuits

i still suck at maths. i didn’t undertand anything on this list :(

• MT

I see now why I have been avoiding this list.

• mulaw

i like this tricks it is very useful i luv dis sites

• bhabna

i found it very useful good way to grasp maths techniques.!!****.

• khem india

i know many more such tricks and i have a book called vedic arithmetic which is an extract from the vedas. the tricks are called the sutras(in sanskrit).

• Rob

Enjoyed these tips.

This is probably a well know trick but my 8 year old son got me with the following:

You pick a number between 1 and 9
Multiply it by 3
Multiply that by 3
You will have a two digit number which you add together he “guessed” my number is 9

• dipa

hi frens thanx alot for contributing so many underlying facts of maths. It has benefitted a lot to me.
Is ther any trick in dealing with large decimal multiplication problems.

• khem india

yes u can use logarithm for large decimal multiplication.

• Chandan Agarwal

Divide any number by 9 in 6 seconds

12348/9=1372
how to do this
1. copy the first number i.e.1
2. Add it with the second number= 1+2=3
3. add the value 3 with the third number i.e=3+3=6
4. add the fourth no. in the same way= i.e 6+4=10.
5 now the no 6 will be 7 (6 +1) as 1 is the carry over.
6. add 10 with the last number i.e 10+8=18
7.Divide this by 9 and write the quotient over there
In case of 8 if it is 7 then the answer of
12347/9 =1371 +8(remainder)
12346/9=1371 +7(remainder)

• Aj

Thnaks to the original writer of this site and all genuine contributors, site has been very helpful. The rest of you why do you waist your time I. A site you don’t enjoy!!! Keep your comments to yourself and move on.

• John Morrison

Math tricks are great for understanding the magic of math. But you should be able to do math in a logical manner. I use a method of math to train my mind for logic and pattern recognition. It is the “hidden number” system. Most people should know the times tables by heart. So for example, if you see 2*6 you will call out 12 without much thought. Sadly, there are still many adults who are not able to do simple mental math.

I have come up with a way to focus the mind on the simple parts and discover the hidden parts of math. Start with pen and paper and work your way up to mental math.

Look at this. 23*45. What are the obvious numbers? From left to right, you can see 8 and 15. Because 2*4 is 8 and 3*5 is 15. What you cannot see is the hidden number 22. The hidden number is the secret to the entire problem. It brings the left and right side numbers together. Learn to spot the hidden number and you will be able to solve 2 by 2 multiplications with ease.

Look at the problem again. 23*45 = 8-22-15. Adding for the left only the tens digits, 8 plus 2 is 10, attach the 2 in the ones column. You have partial answer of 102. Add the 1 from 15 and attach the 5 for the final answer 1035.

You will be doing math from the left side (the more natural may) and when you have a single digit number next to a pair. YOU ONLY PLACE IT ALONG SIDE. Practice with the following problems.

24*36 = Left 6, Hidden n 24, right 24. Add 6 + 2 = 8 and 4, add 2 to 4, attach the last 4.
89*47 = Left 32, Hidden n 92, right 63. 32-92-63. 32+9 =41+2, 412 + 6 is 418 attach 3.
56*47 = Left 20, Hidden n 59, right 42. Do it for yourself.
74*85 = Left 56, Hidden n 67, right ?
96*21 = Left 18, Hidden n ?, right ?

This is not a math trick, but a logical step in processing math.

24*36 = 864
89*47 = 4183
56*47 = 2632
74*85 = 6290
96*21 = 2016

• Ali

In addition to trick No. 10

Multifly by 25: Divide by 4 then add 00 (2 zero) to last diigit.

For dividision by 25: Move 2 decimal places to left then multify by 4.

More power!

• w

Interesting trick – 166 – but notice how the method by which the hidden number is obtained is not revealed?

• sweetammu

its too long & out of fashion

• aashu

its really great!!!!!!!!!!!!!!!!!!!!
it helped me a lot.
thank u.

• Deepak

Trick 9 is from Vedic Math rules. The rule in this case is “All from 9, last from 10”

• mayank

thats a gud site.
u r working nicely dudes……..

• V-RUZ

im exposed all these tricks were up my sleeve lolz, seriously though this is good stuff thanks

• V-RUZ

free trick

(by the way by A2 i mean A squared and 2A means 2*A

step 1) let A=B
step 2) A2=AB
step 3) A2+A2=A2+AB
STEP 4) 2A2=A2+AB
STEP 5) 2A2-2AB=A2+AB-2AB
STEP 6) 2A2-2AB=A2-AB (Factorising)
STEP 7) 2(A2-AB)=1(A2-AB) (divide each side by (A2-AB)
2=1

• Anonymous

It takes some practice but you can learn to do the multiplication algorithm for two digit numbers in your head (described few times in the comments). To save memory, you have to perform additions after each multiplication and keep a “partly finished answer”. After mastering this method you can multiply any two different numbers from the range 1-100, now that’s 10,000 calculations. (Of course, if you are looking for challenge, you can generalize the method for 3 digit numbers)

Example: 23 * 48
8*3 = 24 # 4 is the last digit of the answer, 2 carries to the next calculation.
2*8 + 3*4 + 2 = 30 # Multiply cross digits and add the carried number. 0 is the second last digit of the answer. 3 carries to the next calculation.
2*4 + 3 = 11 # Multiply the first digits and add the carried number
and we have 11&04 = 1104 = 23 * 48

Another: 78 * 32
8*2 = 16 # part answer is 6
7*2 + 8*3 + 1 = 39 # part answer is 96
7*3 + 3 = 24 # Answer is 2496

• Anonymous

Now, another trick I came up by myself. This may be a bit too advanced to this thread and not even arithmetic but I figure someone can appreciate it. Sqrt means square root. To solve quadratic equations (ax^2 + bx + c = 0) fast:
The general formula you use looks pretty horrible for an untrained eye. Let’s get some sense to it. First divide the equation by ‘a’ so that x^2 will have 1 as the coefficent (the roots won’t change). We are now solving equation x^2+bx+c=0. Notice this, in the formula (with a=1), you can take the 1/2 multiplier inside the square root and it becomes 1/4 (erasing the -4c to just -c). Then you have -(1/2)b outside the root and (1/4)b^2 inside. But the latter is the first one squared! Let’s denote p = -(1/2)b. Now our simplified quadratic formula reads:
x = p +- Sqrt(p^2 – c)

So, to solve a given equation, look at the ‘b’, divide it by -2 and remember this number. Now square it and subtract ‘c’. put a +- between p and the root of the subtraction and you are finished.

Example: x^2 + 6x + 5
b = 6 -> p = -3 ; c = 5
Therefore,
x = -3 +- Sqrt(9-5) = -5 or -1

Another: x^2 – 2x – 8
b = -2 -> p = 1 ; c = -8
Now,
x = 1 +- Sqrt(1+8) = -2 or 4

• Anonymous

And the last trick of mine is the coolest, used to solve q.eds with Sqrted and complex roots fast. You need to remember some squares of binomials and the equation should be nice enough (a=1, and then 2 divides b) (Or you can just have insane mental calculation powers and ignore these conditions).

First the examples:
We want to solve x^2 + 2x + 4 = 0 and first notice that there are no integer roots. Luckily ‘b’ is divisable by 2. We can rewrite:
= (x^2 + 2x + 1) + 3 = (x + 1)^2 + 3
Next we focus on the extracted +3. Take it’s negative and square root that. That’s Sqrt(-3) = iSqrt(3). Second focus on the root of (x+1) which is -1. Add these with +- and you’ve got the answer.
x = -1 +- iSqrt(3)

Solve: 0 = x^2 – 6x + 6 = (x-3)^2 – 3 -> x = 3 +- Sqrt(3)
Solve: 0 = x^2 – 6x + 11 = (x-3)^2 + 2 -> x = 3 +- Sqrt(-2)

To prove the method, assume the q.ed. has the roots p+-Sqrt(q). Then derive (x-p-Sqrt(q))*(x-p+Sqrt(q)) = (x-p)^2 – q and ponder a bit. Hope I gave you a good brainteaser! Study maths folks, it’s awesome.

• rajat

there r good maths tricks i m happy

• Airbus

11 times trick…

I just use the follwing…

e.g. 90 x 11

90 x 10 = 900

90 x 1 = 90

therefore 90 x 11 = 990

:D

• Airbus

jp14 – “there is a trick done with 25 pennies… the object is to get the last penny not the most… you play with a partner and you can take as many as 3 or as little as 1… there is a fool proof way to win everytime see if you can figure it out and post it on your site”

make sure when you take the penny you are on odd number.. :)

• Pingback: ToolBlog » 10 fiese Rechentricks()

• The3ggman

My brain hurts.

• Darshan

Really Very Good Trick of essily Calculation,

i want to trick of big DIGIT Multiply, Divied,

Pls Send ME

• joanne

182. Darshan – May 11th, 2009 at 10:41 pm:
Start => Programs => Accessories => Calculator ;P

i remember seeing a book in our college library entitled “the trachtenberg speed system of basic mathematics” or something. their system is more versatile (includes long multiplication, division and square roots, among others) but also more complicated

• jessyb4u

hi all,
I thankyou very much for ur valuable tricks. it helps me a lot. Can any one help me on this
Any trick to find the smallest of these 1/2,3/7,3/5,4/9.
I also want to know if any shortcut method for multiplying and dividing 3 digit number or more

• dionysus

No.4 is useless i think. In the 3rd year of school in a romanian school every child has to know the Pitagora’s Chart
1 2 3 4 5 6 7 8 9 10

1 1 2 3 4 5 6 7 8 9 10
2 2 4 6 8 10 12 15 16 18 20
3 3 6 9 12 15 18 21 24 27 30
4 4 8 12 16 20 24 28 32 36 40
5 5 10 15 20 25 30 35 40 45 50
6 6 12 18 24 30 36 42 48 54 60
7 7 14 21 28 35 42 49 56 63 70
8 8 16 24 32 40 48 56 64 72 80
9 9 18 27 36 45 54 63 72 81 90
10 10 20 30 40 50 60 70 80 90 100

I think everybody should know this without a calculator

• dionysus

it looked nicer when i wrote it :D. Sorry about that

• dionysus

*jessyb4u
first of all when you have more number use “;” not “,”
1/2; 3/7; 3/5; 4/9
find the smallest number that divides by 2;7;5;9
it takes long to explain how to do that but in this case is 2*5*7*9=63*10=630
now you divide 630 by each (630/2=315;630/7=90;630/5=124;630/9=70)
now multiply each number with the result (Ex: 1*315/2*315=315/630) and you will have the numbers to compare in a more convenient way
315/630; 270/630; 372/630; 280/630
now you can clearly see the biggest, the smallest,etc.
This way works all the time

Another way is to divide them:1/2; 3/7; 3/5; 4/9
1/2=0.50 ; 3/7= ~0.43 ; 3/5=0.60 ; 4/9= ~0.44
(You shouldn’t need a calculator for this small numbers)

But in this situation i would do something else
to find the smallest i would immediatly exclude 1/2 and 3/5 because they are equal or bigger than a half (0.5)
3/7= 0.5-1/7 ; 4/9= 0.5-1/9
1/7 > 1/9 so 3/7 is the smallest
(I would say you shouldn’t need paper to solve this problem, not even mentioning calculator)

• dionysus

*177anonymous
This is not a trick and is definetly not yours, is just a way to solve exercises. this is an average problem for a 15 yo kid.

• dionysus

174 V-ruz
STEP 7) 2(A2-AB)=1(A2-AB) (divide each side by (A2-AB)

you cannot do this
because A^2-AB=0
You cannot divide by 0 (One of the first rules in Math)

• rafeeq

1/3 off 10 foot

• SUNIL

TO answer Nagendra comment No 136

Ask the person to write one more 5 digit No
Below that you write your No by deducting his each digit from 9 (this will be 3rd Number)
Again ask him to write one more 5 digit number(4th No)
Here again in the fifth line write a number after deducting each digit of previous no from 9.
Add all five nos . The total will be the same.
eg.
32307 original no
12345 second no
87654 no you hv written
12345 another one written y him
87654 no you hv written
232305 Total(Written beforehand )

• dhen

• SunnySide

these are the tricks that can only get you so far and can only be used for specific problems

• brainwin

i love these tricks

• jenny???

july 15, 2009 i m not smart in math i am bobo

• godiva

when i looked at this list, all i see is like a big white wall and my mind refuses to even TRY to understand. all my life in school i’ve had traumatic experiences dealing with numbers and math problems.
i’m not stupid. i am south east asian and i can can speak 2 languages and 3 dialects. i excel in english and grammar. i like to read and learn new things everyday. BUT MY MIND REFUSES MATH. what’s wrong with me?!

• sam

fantastic tips but you need to check the accuracy of it

• acountant

Here’s MY nine times trick:
0 9 – 9 x 1
1 8 – 9 x 2
2 7 – 9 x 3 etc etc etc, it works great!!
3 6
4 5
5 4
6 3
7 2
8 1
9 0

IT’S REALLY VERY USEFUL. ONCE WE ARE THROUGH THE EASY TRICKS,IT TAKES HARDLY ANY TIME TO DO CALCULATIONS.WE SHOULD BRING THEM INTO PRACTICE BECAUSE IT’S SOMETHING THAT MAKES US DIFFERENT FROM OTHERS.

• Jatin

Lets see my shortcuts of percentage…

1) 128 is increased by 30% . what will be the increased no.

= 128*1.3 = 166.4

2) 40% of ano. is 50 . what will be 20% of that no.

= 50*20/40 = 25

• Thiyagu

Hi its really very useful…

• jblenoirlives

long time reader but just signed up.
love this site.
love jfrater,Randall,mom424 to name a few..

nice to see some of my indian friends makin a fool of themselves here.
but why blame em? blame their english teachers i guess.
even better blame the brits- if they hadnt made english so friggin popular,we indians wuldnt have to go around sounding so friggin funny to everyone.
heard we sound better when speakin french or german.

cheers.

• The Count

Nice set or shortcuts. When I put together my own list at http://www.discreteideas.com/2009/08/the-shortest-path/, only a few of ours overlapped.

• Nivediny

very nice its so useful for us its is not so fast to do but it is easy to calcuate some one or two tricks is not under stable for me wheather i know i under stand it correct or not any way its so so so so so useful for me thank u thank u so much for your tricks and logic maths

• shelkyle

I am having a hard time with percentages….I like blog #90 but what do I do if the number you are trying to get the percentage of is not a perfectly round number like for example 120? I am sure it is easy I just need a really quick way to figure this out….for a career test. I am really really really bad at math. Also, if anyone knows any other good math exercises for tests like this to help me practice that would be great!

i love all these quick tips!

• shelkyle

Ok ignore the comment about the finding a % of a number like 120…I am a loser….I would however like some answers about the other stuff..Also what about multiplying double digits together quickly? I cannot multiply it on paper pretty quick..but not in my head quick. Something not so deep would be great!

• dd bhai

there is everything means trics are good.

• raj

here i’m with my trick
43*11 Its very easy
let do it
take first figure like this 4_3
now 4+3=7
put 7 betwen first figure 4_3

ans is = 473 amazing na!!!!!!

• bhumika

i like so much this tricks ,its very helpfull in compititve exams ,thnx to all who post their tricks

• Jatin

do u know that any digit repeating itself 6 times will be divisible by 3 , 7 , 11 , 13 , 37 and no. itself.

now what abt this one . if like this plz reply…….more tricks cmng soon

• Jatin

do u know that any digit repeating itself 6 times will be divisible by 3 , 7 , 11 , 13 , 37 and no. itself.

example 666666 or 888888

now what abt this one . if like this plz reply…….more tricks cmng soon

I have been teaching mathametics for last 20 years and now i am using tricks to solve maths problems my student .They are very happy and excited . THANKS A LOT

• akash

thanx for the tricks!!! they all are just awesome!! i like them all!! thnxxxx

• Jatin

Running 5/6 of his normal speed a man is 10 min. late. Now what is his usual time and time taken in this case ?

Sol: Multiply 5 and 10 means 50 min is usual time and he takes 60 min. in this case.

I havnt got any reply , thats why i m feeling dscrgmnt…so plz reply.

• vishal

keep on going

• anshuman

hiiiiiiiiiiiiiiiiiiiiiiiii

• majid khan

these tricks are very helpful if you are preparing for competitive exam.
keep it going.

• lizzie

Multiplication of two numbers of any length.
consider PQRS x WXYZ
(a) extreme right digit is S x Z
(b) Extreme left digit is P x W
(c) The middle digits are
R x Z + S x Y
Q x Z + S x X + R x Y
P x Z + S x W + Q x Y + R x X
P x Y + R x W + Q x X
P x X + Q x W

eg.:-
4053
x 7892
———
28219976
+ 37663 (carries)
———-
31986276

similarly
45
x 39
———
1215
+ 54
———
1755

one more eg:-

345
x 253
———
63975
+ 2331
———
87285

• vikas srivastava

@Miss Cellania (19):

Hi this is vikas srivastava , i just wanna new tricks for math to solve some and other things

• Pushkar

@Reea (1):
hi reea…..how are you..??
i am intersted to being your friend…..call me on 9766871976

• azeem

Dono if someone has already mentioned.
Trick to multiply by 9:(for number from 1 to 9)
9*5=(5-1)_(10-5)=45
9*6=(6-1)_(10-6)=54

• jaiveer

Ialways see math tricks

• jaiveer

I am also support you dude

• vikas

IT IS VERY GOOD I LIKE IT VERY MUCH .BUT IAM NOT SO INTRESTED BECAUSE IAM ALREADY KNOW THESE TRICKS AND MORE

• thavamani

The tricks mentioned here are almost known to all. please give some more extraordinary ones.
i hereby furnish a game of fun. try it with others.

“Take a number lesser than 10.
multiply the number by 2 and then add 2.
then multiply by 5 and add 5.
then multiply by 10 and add 10.
tell the result.”

YOU can tell the number that he/she taken initially and the age finally he/she adds.

how?

subtract 160 from the result. the first digit of the answer is the number he taken initially and the remaining digits reveal his/her age.

• kartik

@tony3s (3):th tricks wer given r easi understandable

• astri

• Tenith

i want a maths good riddle.please sent to [email protected]

• jaiveer

I LOVE THIS SITE VERY MUCH.DUDE

• jaiveer

I LOVE THIS SITE VERY MUCH.DUDEBUT MY FRND VIKAS DOESNOT LIKE THIS BECAUSE HE IS A BIG CHUTIYA

• Mandar

I’s Very nice & easy to understand
Thank u

• Siddhant

% trick
It is very easy
Example:
17% of 250=17/100*250=42.5
It is so easy to do in single digit:
4% of 1000= 4/100*1000=40

• ria

Thank you very much. It is very helpful to me. I want to know more math tricks.

• srikanth.A

i have a doubt in quick square can any one sort it out.
above mention that:
If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. Mulitply the first digit by itself + 1, and put 25 on the end. That is all!
25 square(2) = (2x(2+1)) & 25
2 x 3 = 6
625

45 * 45 = (4*(4+1))&45
= (4*5)& 45
=2045 but

• Jay

You added 45 at the end rather than 25.

• odom

@pidro (85):

• can you tech me about arithtics becuase i don’t know.

• hello can you help me asbout math?

• biku sahoo

192*19= ?

• john

i have a doubt in quick square can any one sort it out.
above mention that:
If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. Mulitply the first digit by itself + 1, and put 25 on the end. That is all!
25 square(2) = (2x(2+1)) & 25
2 x 3 = 6
625

45 * 45 = (4*(4+1))&45
= (4*5)& 45
=2045 but

• Rondy

wow amazing thing! Ok going to Fishki.lt http://fishki.lt to relax after good mathematic break. Thanks very useful!

• Online Math Tutor

Great Tips! I will share it with my students who take online math tutoring sessions from me. Thanks a lot!

• siddhant

take a calendar.ask your friend to mark 9 numbers[in a 3*3grid] in a rectangle in the calendar.ask him/her to add 8 in the smallest number in the rectangle and multiply it by nine.write the total in a piece of paper.this is number a.now tell him to add the nine number.this is number b.now tell your freind to unfold the paper.he wiii be shocked!

• Gewgaws

To add up the numbers 1 to x (any number) :-

multiply x by (x + 1) and then half the result

For example to add the numbers from 1 to 10 :-

10 x 11 = 110
110 / 2 = 55 (you can check this by doing 1+2+3+4+5+6+7+8+9+10 on a calculator or in your head)

This works for any whole number

• Ravi

@jaiveer (222): @Online Math Tutor (242): @Gewgaws (244):

• bima

beautiful list!

• chery

thankyou!this would help me to do maths in faster and easier way…
thanks a lot!

• chery

thankyou…..
this would help me to improve my maths and to do it in a faster ,simpler,easier way..

• jajajaja

Thank you so much! Finding this was such a pleasant surprise. Doing math is going to be so much easier now that I have this to help me.

• vaibhav jain

this is easy tricks

• rashmi patel

excellent way of making calculations so easy to do.

• danish

these tricks are realy good.specially for the preparing of examination.

• Albert C. Añasco

NICE TRICKS!!!

• poornima

tricks are good but give more explanation to percentages & tough multiplication. could u explain that detaily.

• view dosi

hiiiiiiiii … this is very cute …. i like this … very much

• nirmal zacheria samuel

tell your frind think a number between 80and 100 tell him/her to turn it and add then ask your friend to tell that 2digit number or 3digit he/she got then you want to ask which is the last number.if it is 2digit number the last number will be the first numberand if it is 3digit the middle number will be one more than the 3rd number and the first number will be 1

• What about getting an Easy square root?
I’m troubled with square roots

• Deji

You know that the square of 17 is 289. The square of 175(17 & 5) will be what?

289
+ 17
—–
306
—–
therefore 175 square is 306(25) ie 30625.

The square of 32 is 1024. What is the square of 325 (32 & 5)?

1024
+ 32
——
1056
—–
so 325 square is 1056(25) ie 105625.

1 last example
the square of 44 is 1936. What is the square of 445 (44 & 5)?
1936
+ 44
——
1980
——
so the square of 445 is 1980(25) ie 198025

Hope this was useful.

• Deji

Ok, another one;

What is the square of 125? thats (1 & 25). Look at this carefully…
the square of 1 is 01 and 5 * 1 = 05 so.
01
+ 05
—-
015
—-
that’s 015(625) thats 015625.

what’s the square of 225? That’s 2 & 25. The square of 2 is 04 and 2 * 5 is 10. so.

04
+ 10
—-
050
—-
that’s 050(625) ie 050625

• manish

suare of 289

That’s pretty lot of math tricks for a number ignorant like me. Hahaha! I wonder why I haven’t learn those things in high school and college days. I guess I’d had a better chance of getting high grades then if I knew these things.

• Hi ppeps

this is sooo cool

I also know a good way of multiplying by 2

DOuble the NUMBER!! lol

JK

Really good website and plus I am amazed by the number of comments!!!!!!!!!!!

• IcHigO

.thanks for the tricks, it increased my grades in math.

.hope that you can make more awesome math tricks.

.good luck!

• khushi

tricks r so interesting i don’t like maths very much but its amazing & learning

• Munir

wonderful

• babji

@kartik (226):

• max

cool its fun too now all these tricks thanks

xd ;) :)

• Ram

i need maths faster calculation tips please send me

[email protected]

• naveen

It was interesting to me.
I apply this technique in my subjects
i have informed to my friends they where get interested….

• Shah

wow… what a wonderful & L-O-N-G list….lots of tips…lots of knowledge….Tis is COOL..

• Anjorin Kehinde Ipetu-Ijesa

square root of numbers.e.g find square root of 961.firstly find that of 1,then that of 9.which is 3 and 1,answer=31.

• Archit

After visiting on your site it feels me that i get an ocean of short trics.
Thank you.
Please send me some more short trics for
multiplication of three digits
division of three digits
sqare of two or three digits
on my email id.

• mehr

i need some more tricks these r gud but if u can provide me some more i’ll b thankful 2 u

• karan

i need some more tricks

• apoorva

hi
wats up

• JOJO

Its very useful and good one, thanks!

• dev d almighty

@sverrirp [36]: why do u multiply 2(3+1)?????its 3*(3+1)

• vinay

What’s east to calculate as large amount in few seconds without calculator. It is amazing. Keep it up.

This a real knowledge bank.

Hare Krishna

• Sonu

Ok Vinay you say right and i will send you some more tricks

• yash

heres a trick for all u guys-
whenever u multiply any no from 1 to 9 with any no of ninie then simply multiply that digit with 9 and write them with some space in between then count the no of 9;s in the no and then write one less nine than the no of 9;s in the no to be multipied and write them in the space u left
eg- 9999 multipied with 4 = 39996 as 9 into 4 is 36 and as there r 4 nine’s in the no i have written 3 of them in d answer

• aman

terrific site…………….thats only i can say …………….thanx alot……………………and plz brng more tricks……..

• chona ubas

alam ko na ditu pala kumukuha anq teacher ko na si sir velasco nanq tricks about mental calculation

• mani vats

I like the trick no. 1,2,3,but the trick no. 4-7 is not clear in the cocept. your trickno. 8 is very large process and the trick no 9 can also be modified in very easiest method and the modified trick can also take less time as comparitive to this. TRICK NO. 10 IS VERY GOOD.

• charan

very good from charan

• roshan singh rawat

there is some most usefull tricks to finding solution immidietly so i has thanks to you and your website y to
give me suitabale and usefull instruction and tricks thanku very much

• Sarsiz

This site helps me a lot.

• d p babu

it is very useful for all ,when i was swa this site ifelt very happy.

• rachit

it rocks

• Rachit

it ia very easy to do now

• rachit

i'm lovin it

• haresh parekh

It’s very amazing trick, pl. saw me another, really very interesting & fantastic arithmetic tricks

• rachit

cool

• rachit

many people will like it——-i am sure

• Rajkumar

hello,
i am mca fresher
and i need shortcut tricks .
so please send me on my email id.

thanks,
regards,

• saravanan

this every important in everyone………… thanking

• ponnuswamy.C

very nice

• Thahseen Ahmed

very intresting site and useful also

• shubham gupta

join 4 the same http://www.shubhamgupta.ibibo.com
9259870006

• ANURAG (BABUL)

Dear/sir
Tish site is very interesting and i liku you s i need to and tish site attch my email id

THANKS:

ANURAG

• ANURAG (BABUL)

Dear/sir

Tish site is very interesting and i liku you s i need to and tish site attch my email id

THANKS:

ANURAG

• shivani

hey……dis site is very interesting.i like maths and tricks to solve.

thanks

ahahaha??!!!?!!! wat a tricks??!!!it makes my brain busssstedd??!!!!

• VINNY

It’s so good I like math because it’s makes my brain sharp…

• KP SINGH

THESE ARE VERY USEFUL TRICKS, I’LL USE THESE TRICKS IN MY BANK EXAMS.

• prashanth

this is prashanth i want multiplication for decimal numbers

• Pingback: nourishing obscurity » Quick arithmetic()

• chiru

hi i am preparing bank exam so i want maths easy methods

• kazishah

I also have one mathmatical trik for square?for example
1 1
4 3
9 5
16 7
25 9
36 11
49 13
64 15
81 17
100 19
the above coloums means square of 2=1+3=4
then square of 3 …4+5=9 and square of 4….,9+7=16,………..sqaur 0f 11=100+21=121……..etc

• ajay 09416139270

intersted its

• ayessa

its not to harad in solving that tricks can you givea hard one that cnnot easily solve with a secondyear student like our section

• Abhishek

• Shraman N L

?? ???????? ?? ???? (???? ???? ? ???? ?? ??? 10)‎
??? ???? ?? ?? ????, ?? ???? ?? ????? ????? ?
?? ???? ??? ????? ??, ???? ??? ?? ?? ?? ???? ? -?????? ????
??? ???????? ?? ???? (??) ?? ?????
‎"???" ???????? ???? ????? ? ???? ???? ???? ????? ?
?????? ?????? ?? ????? ? ??? ???? ??????? ????? ?
‎"??? ?? ???????? ?? ?? ? ??? ????? ???? ?? ?? ? -?????? ???? ????

• humaid

the first trick is nice but could'nt understand other

• abhinav

its a auspicious site it has many useful tricks, i loved it

• Priyanshu Saxena

hello sir,

with the discussion of all of you people i hv got 17 pages tricks

thanks a lot

• Rahul

YOU ALL ARE WRONG

• raudha

multipy 2 number

example 1:26 x 24

6x 4 =24

2 x (2+1) =6

so 26 x 24 = 624

example 2:73 x 77

3 x 7 =21

7 x 8 =56

73 x 77 = 56 21

note : 6 +4 =10 and 7 + 3 = 10

good luck

• Sir Togish

• Sir Togish

A Weldon job….

• Send me

• Asif Rashid

Wow!!!! I loved this and i just loved this.

• shaji bai

thanks for sharing

• choky boy

thanks

• manoj giri

these are the good method for the unemployers who want to crack the exams thankyou for helping us

• :.. I am really thankful to this topic because it really gives great information ,~*

• Randy Lynch

I Think you site is cool, but I have a hard time with the different size numbers.

• vignesh

thanks for giving some hints of mathematics

That’s just awwwwsomeee..
Will b lukin 4 more such tricks…
Thanks 2 all of U Guys-n-Gals..

It is a very useful web. I am very happy with it . If there any onother sort trick so plz send me. Thank u lot.

• manav

good trick

• Name;kaja najumudeen

• Sujith

awesome!!!

• Dryncscania

???? ??:)

• anand wgl

its amazing

• Harish chakrawarthy

For easy math squaring shortcuts and multiplication shortcuts contact me at [email protected]

For example to show one of my methods:

To square a two digit number, say 74

7^2=49
(7*4)2=56
4^2=16

now add the digit other than the ones digit with previous number.

1. 49 cant be added with a previous number.
2. add the 5 of 56 with 49, 49+5=54 then simply attach the ones digit.becomes 546
3. similarly add 1 of 16 with 546 and attach 6.

you get 5476.
this is the square of 74.
i.e. 74^2=5476 :-) :-) :-) :-) :-) :-)

• chirag patel

cant understand your trick ,please give some more example like for 35

• Harish Chakrawarthy

For easy math squaring shortcuts and multiplication shortcuts contact me at [email protected]

For example to show one of my methods:

To square a two digit number, say 74

7^2=49
(7*4)2=56
4^2=16

now add the digit other than the ones digit with previous number.

1. 49 cant be added with a previous number.
2. add the 5 of 56 with 49, 49+5=54 then simply attach the ones digit.becomes 546
3. similarly add 1 of 16 with 546 and attach 6.

you get 5476.
this is the square of 74.
i.e. 74^2=5476 :-) :-) :-) :-) :-) :-) bye bye

• chirag patel

nice one…………………..

• shasha

oooowwww…so useful…..thanks…..

• Mathematician

I have trick for working out 25-times tables:

For 25 x 8, divide 8 by 4 and multiply by 100. So you divide the number that is not 25 by 4 and multiply by 100. This works for all numbers.

If you get a decimal number you can still do it.

Examples:

25 x 13 = 100(13/4) = 100 x 3.25 = 325
25 x 68 = 100(68/4) = 100 x 17 = 1700

Larger examples:

25 x 58396 = 100(58396/4) = 100 x 14599 = 1459900
25 x 1624739 = 100(1624739/4) = 100 x 406184.75 = 40618475

Dividing by 4 is pretty easy:

Divide by 2, then divide by 2 again.

Also, for those who like algebra, this is the formula (n = whatever number your multiplying):

100(n/4)

Hope this helps!!

• saharsh

easiest method of factorisation

• chirag

nice

• Ray

The only problem I have with your math is, You should never need to figure out a 15% tip. 20% is standard. Take the total x .2. Add that to the total and all will be well.

• manoj

hi sir
plse send me formula all in my id so that i can read easily plse mail me

• MUTHUKUMAR

VERY USEFUL TIPS THANK U

• Maria Smith

These are very interesting tricks. Math always a problem for me. I try these tricks for my solutions. Thanks for sharing such important tips.

• raj

super

• venkatesh

good tips

• Kehsibashok

Wow wonderfull Tricks . I want more and more tricks . Please upload them here soon .

excellent

• shubi

nice tricks
:P

• saurabh ranjan

hi
do u want to know 11 trick for infinite no.

• me

how can i fast to learn that tricks?

• Hari om

it is very good for banking sectore boyes and girles. i want to thank to this site.

• mohd usmaan

I have a math short trick of multiplication which is very important…

Ifyou want to multiply two numbers e.g. 54*26

5 4

| * |

2 6

————-

1 4 0 4

————-

4*6————-> 2 4

5*6————-> 3 0

4*2————-> 0 8

+——–

4 0

5*2———–>1 0

==========================

1 4 0 4

• Justin Bieber

hello everyone whos on this always and i mean always! follow your dream!
That math is very clever
keep it up people

• mo

it is bleddy

• rahul

these are very simple tricks.you should gave new tricks.

• EnjoyKISShore

percentage calculation is vague and want more tip to multiply a lagre number by a large number…but thanks a lot for this…

• prakash ghodke.

how to solve ssc ganeral maths and science and technology?

• k. balaji

hai this is balaji i like maths which wil help u in future take care always in touch with maths

• Samuel

Very very heartf ul thanks for providing precious ticks

• hemant shedge

• hemant shedge

if u want square of 98 98 is less 2 to 100 so 98-2=96 and add square of what u less means 4 answer 9604 eg. squre of 96
96-4=92&16

• sillu

Its very interesting.

• VILAS M. THKUR

I am trying to get the formula of accuracy of Multiplication (calculation without actual multiplication ) Viz. if we want to multiply 123456 * 2564257 = ? what so ever the actual Multiplication will be .The Sum of the digits of the Answer will be 3 ( three ) . Now the Ans calculated by the Calculator comes out to be 316572912192 .( accurate Ans .) If we calculate the Sum of the Ans will be 3 as Predicted earlier by me . Am I right or is there any other method to predict the Accuracy of the Product ! Pl do write to me on my mail address . Again 84637 * 25642 = ? Sum of the Ans will be 1( one ) only Pl find the accurate Ans & tally the accuracy with Sum 1 .

• anika zimarah

THIS TECHNIQUES ARE SO USEFUL. THANKYOU :)

• Chitra patil

It’s good!
Very nice,hmmu.
Yeah i got full marks in math but my calculation is not good,i got very problems.
But through dis page i got help.now i learn more about it & i m confiedent dat .i got scolarship in maths .
Awesome

• kok singh

• Vilas M. Thakur

All the 10 Airthmatics Tricks are very Good & Easy to calculate . Fianlly to Say if We learn the TECHNIQUES then we can Calculate the Biggest Multiplication with 100 % Accuracy ! THANKS A LOT !!

• Vilas M. Thakur

Hello ,this is something different as what I think .If we Multiply 63527 & 876396 whatever be the Ans SUM of the Digit of the Ans is 6 . Similarly 65 * 65 =4225 , total comes out to be 4 .Please Try any other Ex. & Please Do write to me if I am incorrect .

• jessica

Hi i was just wondering if someone could please give me a quick and simple theory on how to do percentages on a calculator without a % button. Thanks :)

• Divyansh

Really gud tricks. i say i will tell it to my frnds too

• alankar

i loved your post.. helped me a lot thanks keep posting more and if u allready have some for chemistry or physics plz email me..

• shankar

interestin..

MTECH COMPUTER

• vivek

teri aisi ki taisi

• vivek

2+3/3+35-6+586
(62*65+82)=?

• anushree

my god in the past i did not like math but after seeing this site i think math is an intresting subjects thank you the person who developed this site

• Eric

#2 is incorrect as well. yes that works for 25, but if you try 35 it fails. 3×3=9+1=10, so according to the directions in #2, 35×35=1025, when in fact it’s 1225. neat tricks but not all are correct.

its better of all formula’s
I am absolutely satisfied with you

• Olumoyegun Akinola

I love mathematics…

• Olumoyegun Akinola

Math matters…

• Olumoyegun Akinola

Math is Life…

• shuvankar

i love maths and maths is my favarite subject but after getting this interesting tricks i am more interested in the maths subject.

• Fred Osei

I’ve really improved on my lot when i visited this site. It’s really fantastic antastic

• vi

In this Site ,Fantastic ideas and formulas developed by a mathematician are very good and interesting ! If somebody is not interested in Math’s , he can also give good Results to his Satisfaction !!

• Vilas M. Thakur

In this Site ,Fantastic ideas and formulas developed by a mathematician are very good and interesting ! If somebody is not interested in Math’s , he can also give good Results to his Satisfaction !!

• Vilas M. Thakur

Hello ,this is something different as what I think .If we Multiply 63527 & 876396 whatever be the Ans. SUM of the Digit of the Ans is 6 . Similarly 65 * 65 =4225 , total comes out to be 4 only. Please Try any other Ex. & Please Do write to me if I am correct Or incorrect . Viewers may Write If I am Right Or You might have heard Earlier . So that I am able to Write some another Interesting Math’s techniques for viewers !

• sev

now can you teach us a trick in Calculus

• tuikorosam

NICE ONE…sentence structure for No.2 is somehow incorrect…

• tarun

useful ……………….

• anku

tnks man

• shivani

i dont like maths

• divya

i love maths. my favourite subject is maths. it’s so interesting

• darshan

i love maths a lot

• dau singh

this site is useful to increase brain power as maths

• ANAND

If you want to square any no ends with 5.
for e.g. 85*85
1. separate the number 5 is at one side and remaining is at another side
8 5
2.As we know that square of 5 is 25 write down it.
25
3.Multiply another number with it’s next number.
8*9=72
4. Write the above result before 25. This is the answer.
7225

• jeevika

it is very nice and very easy steps to do maths

• VIVEK SINGH

thanks its help us

• VIVEK SINGH

thanks its very useful for me

• Nabeel Khan

Amazing tricks. . .

Though some of them went up my head. . .

But the ones I understood, are really worth it.

• Sumit Dasthakur

thank you for providing us such nice math tricks .please give more tricks that we can easily solve any calculation without calculator.
once again thank you

• kuldeep

/ 16 Sep, 2007 at 10:02 pm

I didn’t know about trick number 10.

And it seems there is a good reason for that, because it doesn’t work !

e.g.: 58 / 9 = 6r4

but according to the trick: 5r4

e.g.: 587 / 9 = 65r2

but according to the trick: 54r2

So this trick doesn’t work all the time.

The only thing that’s true is that summing all the numbers gives the remainder (I knew that).

But good post to remind people math doesn’t have to be hard.

Graeme / 28 May, 2010 at 06:40 pm

for starters you need to learn to read, trick number 10 = 10. Assorted Multiplication Rules

as far as i can remember 58 / 9 = division?

fahim / 3 Sep, 2011 at 05:36 am

but here no trick is about 10 tell me which one?

Reea / 17 Sep, 2007 at 04:07 am

I always sucked at math, this is useful, another interesting list, love your site!

jfrater / 17 Sep, 2007 at 04:27 am

Reea: same here – this list stems from my trying to find something to help me fix my mess of a mathematical brain.

jfrater / 17 Sep, 2007 at 05:39 am

tony3s: You are right – I have replaced 10 with assorted multiplication rules because the previous number 10 does only work in certain circumstances.

awesome list. i inadvertently learned some of the tricks listed here. but i used to memorize math…

blazak / 17 Sep, 2007 at 10:00 am

The trick for multiplying by 9 is good, but I always thought you’d look like an idiot in math class staring at your fingers, so my trick was simply…the answer will add up to 9, with the first digit being one less than your original multiplier…

ex – 7*9 = 63 (6 is one less than 7, and 6+3=9)

jfrater / 17 Sep, 2007 at 10:33 am

Dan / 17 Sep, 2007 at 12:04 pm

I prefer calculators… but I do know a few of these tricks and they are helpful when I don’t have one.

The China Tattler / 17 Sep, 2007 at 12:39 pm

My brain freezes when numbers and words are combined.

I know most of these things, I can do them without thinking. But, when I read how to do them, I just zone out.

It just seems too confusing, like trying to translate English into Chinese characters using pinyin.

Math has its own language.

Shad / 17 Sep, 2007 at 12:40 pm

#3… 2682 / 2 = 1341 (even number so add 0) …

Isn’t 1341 an odd number? the math still works, but I’m all sorts of confused now. And I’ve always sucked at math

Michael F. Cox / 11 Aug, 2010 at 09:43 pm

It’s WHOLE NUMBERS vs. FRACTIONAL NUMBERS, not Odd vs. Even.

(Maybe it has been updated since your comment.)

Tom Steele / 17 Sep, 2007 at 12:43 pm

Neat stuff, but #3 appears to be incorrect.

It says if you have an even number, you add a zero to the end and if you have an odd number you add a 5 to the end.

I believe they mean to say, “if you have a WHOLE number add a zero to the end, and if you have a fraction/decimal then add a 5 to the end.”

1341 is an ODD number, not an even number. But it IS a WHOLE number.

jfrater / 17 Sep, 2007 at 01:01 pm

shad and Tom: thanks – corrected.

Strath / 17 Sep, 2007 at 01:43 pm

#3 is just the reverse of #8. Divide by 2 and shift the decimal place. No need to remember even/odd whole/fractional rule.

2682 * 5

Step1: 2682 / 2 = 1341

Step2: Move the decimal: 13410

5887 * 5

Step1: 5887 / 2 = 2943.5

Step2: Move the decimal: 29435

Strath / 17 Sep, 2007 at 01:51 pm

Oh, and #1, simpler method to multiply by 11 and it works for any number of digits.

Multiply by 10 and add the original number.

jfrater / 17 Sep, 2007 at 02:16 pm

anteater_sa / 17 Sep, 2007 at 04:12 pm

Some cool tricks here, heres another, to find if a number is a multiple of 3, add all the numbers together and if they are evenly divisable by 3 then it is. e.g: 9576 –> 9 + 5 + 7 + 6 = 27 therefore 9576 is a multiple of 3

Yanni / 17 Sep, 2007 at 04:24 pm

We teach many of these “tricks” in our Mathnasium Learning Center (www.mathnasium.com). Sorry for the plug, but here are some interesting “tricks.”

Find 7 % of 300. Sound Difficult?

Percents: First of all you need to understand the word “Percent.” The first part is PER , as in 10 tricks per listverse page. PER = FOR EACH. The second part of the word is CENT, as in 100. Like Century = 100 years. 100 CENTS in 1 dollar… etc. Ok… so PERCENT = For Each 100.

So, it follows that 7 PERCENT of 100, is 7. (7 for each hundred, of only 1 hundred).

8 % of 100 = 8. 35.73% of 100 = 35.73

But how is that useful??

Back to the 7% of 300 question. 7% of the first hundred is 7. 7% of 2nd hundred is also 7, and yep, 7% of the 3rd hundred is also 7. So 7+7+7 = 21.

If 8 % of 100 is 8, it follows that 8% of 50 is half of 8 , or 4.

Break down every number that’s asked into questions of 100, if the number is less then 100, then move the decimal point accordingly.

EXAMPLES:

8%200 = ? 8 + 8 = 16.

8%250 = ? 8 + 8 + 4 = 20.

8%25 = 2.0 (Moving the decimal back).

15%300 = 15+15+15 =45.

15%350 = 15+15+15+7.5 = 52.5

Also it’s usefull to know that you can always flip percents, like 3% of 100 is the same as 100 %of 3.

35% of 8 is the same as 8% of 35.

Michael F. Cox / 11 Aug, 2010 at 10:04 pm

You say “35% of 8 is the same as 8% of 35.”

That’s because Multiplication is Associative, meaning that the ORDER

in which you group the items to be multiplied is wholly irrelevant.

(0.35 times is the same as (35 times 0.08)

So saying that 35% of 8 is the same as 8% of 35 is simply

“associating” the .01 (the decimal equivalent of 1%) first with

the 35 and then alternatively, with the 8.

Premise:

( 35 percent ) * 8 = 35 * ( 8 percent )

Proof:

( 35 * 0.01 ) * 8 = 35 * ( 0.01 * 8 )

Moot point: The above equation is equal to [ ( 8 * 35) * 0.01 ]

This Space Intentionally Left Blank / 18 Sep, 2011 at 03:49 am

For and equation like 35% * 8

I would break this down to simplify

= 35% * 8

= 35 / 100 * 4 * 2

= 35 / 100 * 2 * 2 * 2

= 35 * 2 * 2 * 2 /100

= 70 * 2 * 2 /100

=140 * 2 / 100

=280 /100

=2.8

If you break it down you should be able to do it in your head

ow3n / 17 Sep, 2007 at 04:30 pm

One trick I use that I didn’t see listed is multiplying large numbers.

Like:

12 x 734

can be broken into ((10×700) + (2×700) + (10×34) + (2×34)) = 7068

or

8 x 6846

can be broken into ((8×6000) + (8×800) + (8×40) + (8×6)) = 54768

basically you break the number into tens, hundreds, thousands, etc and mulitply each group. with some larger numbers it can get hard to remember each “sub-number” but if you’re trying to estimate, its a good way to get a rough idea.

great post otherwise, i learned a lot of tips i wouldn’t have thought of otherwise..

~ow3n

ben / 17 Sep, 2007 at 05:26 pm

I wish I would have had this a few years ago! Now im in high school calculus, its a little harder than these rules apply still great!

Miss Cellania / 17 Sep, 2007 at 05:54 pm

To multiply something by five, I always multiplied by ten, then halved the answer.

ganesh / 25 Jun, 2011 at 04:23 am

Nice one

Fe / 17 Sep, 2007 at 06:47 pm

Gotta agree with China Tattler, trying to read how to perform math tricks is like trying to sing a fragrance, it just doesn’t work for me. I worked in a fabric store for four years and pretty quick picked up all sorts of tricks to calculate percentages, discounts, fractions and decimals all in my head, but explaining them confuses just about everyone.

Ben / 17 Sep, 2007 at 07:49 pm

Here is a trick…

I turn on the calculator and start typing!

JK

These are great tricks essp for the kids still in high school and middle school. The joys of college math is the same but you dont use numbers just english and greek letters.

penny / 17 Sep, 2007 at 09:36 pm

A better system:

The Tractenberg System Of Speed Math.

Also check out:

For advanced tricks–such as superspeed Langrange

Division.

jfrater / 17 Sep, 2007 at 11:52 pm

Yanni: That is the most useful mathematics tip I have ever heard. Thanks for adding it – brilliant!

qureyoon / 18 Sep, 2007 at 12:45 am

this is amazing ! i only knew few of these tricks

thanks for sharing ^^

Andre du Plessis / 18 Sep, 2007 at 01:26 am

1, 2 and 3 I knew about (you can excercise them with the following feed – http://www.mental-workout.com/)

about 1 : I also worked out you can do the same with 3 numbers eg.

172 * 11

1(1+7)(7+2)2 = 1892

I am pretty sure you will be able expand on that even further.

5 and 6 did seem obvious to me.

9 I would rather go to the nearest 100 eg. 1000 – 700 = 300 and then do an easy 100 subtraction 100 – 48 = 52 then add them up 300 +52 = 352 (may seem longer but actually goes pretty fast in my mind)

Thanks for the others

Dhammika / 23 Jun, 2010 at 12:14 pm

Your system is very nice. But if u get 182*11 what will be the system for calculation. pls tell me.

Michael F. Cox / 11 Aug, 2010 at 10:10 pm

I do it a bitdifferently…

1 8 2

+ 1 8 2

It’s what they taught us is Grade School… using zero as a place holder…

10 x 182 = 1 8 2 (0)

+ (1 x 182) = 1 8 2

——————

2 0 0 2

umesh / 23 Aug, 2010 at 09:17 am

ur method is great and useful to anyone . thank u very much. if u have other short-cut tricks of math please send me

Paul Joakim / 18 Sep, 2007 at 02:41 am

Another approach is the “is x divisable by y?”-question:

A number is divisable by 2 if it’s an even number.

3: The sum of the individual digits is divisable by 3, e.g. 174 => 1+7+4 = 12 (=> 1+2 = 3)

4: The last two digits is divisable by 4

5: The last digit is 5 or 0

6: The number is divisable by 2 and 3

7: Double the last digit and subtract it from the rest. If the result is divisable by 7, the original number also is. E.g. 483 => 48-(3*2) = 42, divisable by 7

8: The last three digits is divisable by 8

9: The sum of digits is 9

10: The last digit is 0

11: Subtract the sum of “even” digits from the sum of “odd” digits – if divisable by 11 (incl 0), the original number is divisable by 11: E.g. 7084 => (7+8)-(0+4)=11. 7084 is divisable by 11.

Robert / 18 Sep, 2007 at 07:43 am

I always liked the trick to determine if an integer is divisible by 3 – just add up all the digits in the number, and it those digits are divisible by 3, the original number is divisible by 3. 114 = 1+1+4 = 6 – 114 is divisible by 3.

Professor Homunculus / 18 Sep, 2007 at 09:32 am

Check out MathMojo.com for other tricks and tips. There is a link to a good, interactive lesson on multplication by 11 and 12 for huge numbers on the homepage.

frogandpig / 18 Sep, 2007 at 11:39 am

I have always figured out how much a certain percent is by using either 1% or 10%, then easy basic math.

Example:

4% of 430 = ?

1% of 430 = 4.3

4.3 x 4 = 17.2

or

(4×4)+(.3×4)=16+1.2=17.2

15% of 58 = ?

10% of 58 = 5.8

5% of 58 = 5.8/2 = 2.9

15% of 58 = 5.8 + 2.9 = 8.7

or 10% = 5.8 and 1% = .58

.58 x 5 = (.60 x 5) – .1 = 2.9

Rounding works great for tips at restaurants

15% of \$58 = ?

15% of \$60 = 10%(\$6) + 5%(\$3) = \$9

And if you round but still want the exact amount, subtract the percent you’re trying to find from the additional amount you rounded. (Works easier for large numbers, but the concept is the same.)

60 – 58 = 2

15% of 2 = .3

9 – .3 = 8.7

Decimal places are moved easily in my mind, so maybe this trick only works for me?

keisha / 20 Feb, 2011 at 02:28 am

Thanx but these top ten arithmatic tricks did’nt really help me as i got confused half way through a couple of them so if i was you i would make it easier to UNDERSTAND!

sverrirp / 18 Sep, 2007 at 12:47 pm

Trick number two doesn’t work out:

35*35 = (2x(3+1)) & 25

2 x 4 = 8 = 825 according to the trick

But 35*35 = 1225

HunterDad / 6 Oct, 2010 at 06:43 am

You need to read the trick better. MULTIPLY THE FIRST NUMBER BY ITSELF PLUS ONE.

35*35 = (3X(3=1)) & 25

3×4 = 12 & 25

1225.

arvind / 25 Sep, 2011 at 06:01 am

lol its 3x(3+1) not 2x(3+1)

imajoebob / 18 Sep, 2007 at 03:33 pm

Why didn’t you follow your own tax tip rules for multiplying by 15?

Instead of multiplying the first factor by 10, and then the second by 5, which some people may find difficult, just multiply by 10 (i.e. add a zero) then divide by 2 and add it to itself.

237 x 15 =

(237×10) + (237*10)/5 =

2370 + 1185 = 3555

Or you can always multiply by 100 and use your 15% tax formula.

Tom H / 18 Sep, 2007 at 03:48 pm

A better tip for multiplying by 6: multiply by 5 (as stated) and then add the original number.

I find this easier than multiplying by 3 then 2…

monsolo / 18 Sep, 2007 at 04:22 pm

Here’s a quick tip to multiply any two numbers that are between 11-19 (like 13 * 15):

1. Take the first number (13) and multiply by 10

(13*10)=130

2. Take the last digit of the second number (5) and multiply by 10

5*10=50

3. Add the results of steps 1 and 2

130+50=180

4. Get the last digit of the first number (3) and the last digit of the second number (5) and mutiply the two

3*5=15

5. Add the results of step 3 and 4

180+15=195

Try it. It sounds complicated but once you remember it, it gets useful

achan / 18 Sep, 2007 at 05:10 pm

Found this neat trick about the 11 rule – expanded.

What is 51236 X 11.

First step, 051236

Second step, 5(5+1)(1+2)(2+3)(3+6)6

Found it here

Ace / 18 Sep, 2007 at 07:09 pm

Awesome tips guys! Also.. Monsolo, I like yours too. Thanks!

Jim C. / 18 Sep, 2007 at 07:53 pm

To convert between ounces and pounds, divide or multiply (as required) by 2 four times.

The same applies for price per ounce and price per pound.

hypergene / 18 Sep, 2007 at 08:10 pm

@sverrip

Trick 2 is correct:

35*35 = 3 x (3+1) & 25 = 12 & 25 = 1225

45*45 = 4 x (4+1) & 25 = 20 & 25 = 2025

55*55 = 5 x 6 & 25 = 30 & 25 = 3025

onikirol / 18 Sep, 2007 at 09:02 pm

even numbers multiplied by 6:

6×2= 12

6×4= 24

6×6= 36

6×8= 48

the even number is placed as the 2nd digit, and half of it is placed as the first. (the first step always applies, but the 2nd step is only true for 2, 4, 6, and 8 )

and for multiples of 5, I’m like Miss Cellania in that I go for multiply by 10 and then half it

MikeB / 18 Sep, 2007 at 09:43 pm

You might want to look at this book: “The Trachtenberg Speed System of Basic Mathematics” which explains for example how to multiply two large numbers without the need for calculator or paper.

jfrater / 18 Sep, 2007 at 10:44 pm

imajoebob: you are correct, but I wanted to mention as many options as possible because of the very reason you state – some people find different methods easier – two methods are better than one

Thanks guys for the extra tips – they are all really useful and make for an excellent resource.

Colin Seymour / 19 Sep, 2007 at 02:39 am

Fantastic list. I use a fair few of these already, but have certainly learnt a few more. Trick 9 applies to 10 to the power of any number – 10, 100, 1000, 10000 etc too.

jfrater / 19 Sep, 2007 at 02:44 am

Colin Seymour: thanks I am glad it will be of use to you – thanks also for expanding on trick 9. These comments are as useful as the list

Rui Martins / 19 Sep, 2007 at 03:23 am

Actually, Rule Number 3 (Multiply by 5) is a complicated form, of explaining what already is said in in First Item in Rule Number 10 (Multiply by 5: Multiply by 10 and divide by 2)

And this is very simple to understand because, 10/2 = 5

so,

2682 x 5 = 2682 x (10/2) = 26820 / 2 = 13410

or if you prefer to halve first

2682 x (10/2) = (2682/2) * 10 = 1341 * 10 = 13410

No weird rules for 0 or 5 just plain multiplication and halving

Remember that multiply by 10 in decimal (base 10 system) is easy, just add 0 to the right.

And halving something is second nature to any one which had a brother

portnoy / 19 Sep, 2007 at 03:30 am

Of course any even number is divisible by two but,

If the last two digits of a number are divisible by 4 then the whole number is divisible by 4.

If the last three digits are divisible by 8 then the whole number is divisible by 8…. etc.

The rules about 3 apply to 6 and 9 too.

If the digits add up to be a multiple of 3 and the number is even then it’s divisible by 6.

If the digits add up to be a multiple of 9 then it’s divisible by 9.

Seven is the only goofball.

HunterDad / 6 Oct, 2010 at 07:31 am

“If the digits add up to be a multiple of 9 then it’s divisible by 9”

Uh… Isn’t any number that is a Multiple of X, also divisible by X?

That is like saying that any number that is a multiple of 5, is also divisible by 5.

Kind of obvious?

Jay / 6 Oct, 2010 at 08:15 am

He’s talking about cases where the individual digits ADD UP to a multiple of nine. 3+3+3=9; 333/9=37

sabitri baral / 1 Sep, 2011 at 12:14 am

to get square of numbers like 05,25,35,45,55,65,75,85&95 upto 100 at first multiply the second number by 5 and multiply the first number by adding one on it. for eg:25^2=5*5=25 and put it on second like:_25 and multiply 2 of 25^2 with adding 1 on it.At last multiply 2 with 3 in which you got 3 from adding 1 on 2.then put like this:_25=3*2=625

eg: 25^2=5*5=_25

and

2*(2+1)

=2*3

=6 and put on second

=625

Tuplad / 19 Sep, 2007 at 04:38 am

This is great, I suck at math so this is very handy!!

Woody / 19 Sep, 2007 at 05:09 am

One trick I learned thats useful is how to do square roots when you don’t have a calculator handy. It’s simple and works quite nicely as follows:

Subtract successive odd numbers, starting at 1, until your remainder is less than the next odd number.

Count the number of odds you subtracted, thats your whole part, then put the next put your remaining value over the next odd to get your fractional part.

The fractional part isn’t exact, but it’s usually close for large numbers.

For example:

9 -1 = 8 -3 = 5 -5 = 0

1 2 3

So the square of 9 = 3 (count of 1,3,5)

You can also use addition to get there as well:

120 = (1+3+5+7+9+11+13+15+17+19)+20

1 2 3 4 5 6 7 8 9 10 remainder

So, the square of 120 is 10 and 20/21 (10.9523)

The square of 120 is actually 10.9544, but 20/21 is pretty close and easier to work with if you’re not using a calculator.

If you have a rough idea of where its at, you can also figure out a quick “jump in” by guessing close. The close value can be multiplied by 2, and added to 1 to get the next odd in the sequence. For example, lets do 10535:

For 10535 we know 100^2 is 10000.

(100 * 2)+1 = 201, the next odd to use.

535 – 201= 334 -203 = 131

So Sqtr(10535) ~= 102 and 131/205 (.639 vs .640)

Hope this is helpful to someone!

jfrater / 19 Sep, 2007 at 05:33 am

I am amazed at how mathematical our users are here! Well done.

Oh – and hi to everyone coming from lifehack.org – thanks for visiting and contributing to the comments!

Logi Helgu / 19 Sep, 2007 at 06:15 am
http://en.wikipedia.org/wiki/Trachtenberg_system

swimner / 20 Sep, 2007 at 12:41 am

Relations of square numbers

We can get 15^2 = 225

13^2 = 15^2 – (15+13)(15-13) = 225 – 28*2 = 169

17^2 = 15^2 – (15+17)(15-17) = 225 -(-64) = 225 + 64 = 289

Twisting the trick a bit, we can generate ALL Pythagorean Triplets

Most people will recall a 3,4,5 triangle

Some remember the 5,12,13 triangle

Few remember the 7,24,25 triangle

Most don’t know the 121,7320,7321 triangle

Note that the smallest side is odd.

Simply square an odd number such as 9^2 = 81

Divide in half (not evenly)

An uneven split of 81 is 40,41

So 9,40,41 is a pythagorean triplet

ie 9^2 + 40^2 = 41^2

It also works for even numbers, but they have to have at least one odd factor.

Lets try 10. Find the pythagorean triplet for 5.

5,12,13 and then muliply by the other factor of 10 (namely 2) to get 10,24,26.

For powers of 2 we must be really sneaky.

Take 2^6 = 64.

Divide the number by 4 to get 16.

We know 3,4,5 is a pythagorean triplet.

Multiply the triplet by 16 to get 48,64,80.

We owe this to the Babyloneans (3000+ years old).

rosy / 20 Sep, 2007 at 05:44 am

That pretty excellent and good!! I am really impressed with the way you have come up with the math..I will surely use this technique…

cybernezumi / 20 Sep, 2007 at 12:50 pm

For restaurant tips I usually just double the sales tax, which here is about 7.5% — yielding 15%. If yours is a bit lower or higher, just round up or down a little bit to get it close enough.

Nazzyon / 20 Sep, 2007 at 01:01 pm

I am good @ Maths but my problem is speed/time.

Now I will be able to solve faster than usual. My B’s will definitely fire up to A’s if I make use of these tricks.

Thanks for contributing

pallav / 21 Sep, 2007 at 03:38 am

you people are scary!!

jfrater / 21 Sep, 2007 at 05:34 am

pallav: but they will be earning the big bucks one day (if not already!) Nerds rule

mamoy / 25 Sep, 2007 at 05:18 am

its soooooo amazing

sahil / 29 Sep, 2007 at 07:22 am

its simply superb!!!!!!!!!!!

flower / 29 Sep, 2007 at 11:45 pm

Fear of Maths is only mental.I suggest:

1.Instead of saying DIVIDE BY 2, say HALF/HALVE IT.

2.Instead of saying MULTIPLY it by 2, say DOUBLE IT.

3.Never use more than two digit numbers to prove the working of a method.

4.Show the more interesting sides of maths, for example,show the beauty of the table of nine (which really looks cute, simple and well arranged).

After these small things, leave the person to grow up inside herself, by herself. They’ll start with small victories, and keep gathering courage for bigger ones. Maths IS easy and beautiful upto a certain level. Let’s all enjoy this beautiful, universal language.

wellwisher / 4 Jan, 2011 at 03:33 am

I really liked your thought, but this will not help to solve tough problems……..

Gaurav Tekriwal / 30 Sep, 2007 at 06:32 am

HI!

Isnt all this High Speed Vedic Mental Mathematics from India?

Vedic Math is the world’s fastest mental math method from India- You can do calculations much much faster compared to the normal method or even a calculator.

Check out this site on Vedic Maths which has lots of tutorials and resources.

The tutorials given here on Vedic Maths are the best. Do Check them out.

Hope it helps!

Gaurav Tekriwal
http://www.vedicmathsindia.org

wellwisher / 4 Jan, 2011 at 03:35 am

Thank you for the suggestion I’ll try that………..

Catdancer / 2 Oct, 2007 at 06:13 am

Good to know these things! I’m an elementary teacher and have used a few of these before but not all. As for the finger trick when multiplying by 9, I teach that every year. It’s great for elementary age kids and some higher grades, too.

I have a trick for calculating a tip that doesn’t involve anything tricky. I figure out what 10% of the bill is by moving a decimal point, then I add the amount of the sales tax to the 10% figure. My state has a 6% sales tax so it works well for me. If you had 8%, you could just double the amount of the tax. I never worry about an extra 1% for the tip – that’s usually just a few pennies.

• ARJUN

REALLY AMAZING TO FIND IT. I FEEL MATHS IS NOT SO DIFICULT AS I USED TO THINK.

• gokul

quick square method is not possible in the case of 55
55*55= 3025
but according to your method it is 3055 so please correct this

• utkarsh

it is a ecellent way to learn math

Talking about Percentages, when I see a post at my local store saying 60% off, all I do is this: 100% – 60% = 40%. Then its easy to tell how much you’re paying just by multiplying original price by 4 and moving the decimal back.

For example: orignal price is \$150, and it’s 30% off. Then:
100-30=70
150 * 70 = 1050
1050 = 105 (moving back the decimal) Only \$105 with the 30% off.

Another one: Same original price, 80% off (big sale). Then:
100 – 80 = 20
150 * 2 = 300
300 = 30 (moving the decimal one digit back) you pay only \$30 with the 80% off.

• RAJESHKALYANI

45*45=2025

105*105=11025

solution method
1st step:- last two number will be 25 is certainly
2nd step:- multyply with first number and add same first number
eg:

• marie

awesome ! great math tricks ! i love it !

• Ancy Rose Varghese

much more easy step to find the square of a two digit number ends with 5

Eg.to find square of 25

1. first take square of 5 ie, 25 write it to the right side
2.take next number to 2 ie. 3 – multiply 3 to 2 ie. 3 x 2 =6
write it to the right side of 25 ie 625

square of 25 is 625

#check it with 85

first step 52=25
second next no: to 8 is 9
multiply 8 x 9=72
write it togetherly ie 7225

• GOLDIE

GOOD EFFORT………..THANKS FOR THIS VALUABLE MATERIAL. :)

• mike webber

excellent fun

• Gagan

I want to know the tricks to find the square or cube of the numbers.

• sureshbabu

very nice tips

• garrymoore

Name

• shaswat vashistha

well your trick with multplying an dividing by 5 was good and if you want to square number from 100 to 110 simply square the last digit and add the number

for eg
105*105=5*5=25 and it is 5 more from hundred then 105+5=110
ans-11025

• Vilas M Thakur

Please Give Some more Tricks ( 10 + 1 ) For Viewers ! I Am A Maths Teacher So I Do Apply Maximum Math’s Tricks . This Site Is Very Useful For Me Another Teachers Of Math’s !

• keerthan.n

show me some easy way to do maths

• macaulaypearson

Name

• gyandaata

it is easy trick . tell me the trick to know the cubes http://www.gyandaata.com

• Shailendra Ameta

very nice tricks

• bharat

i love all this tricks and all of this tricks will also be helpful in my studies :)
i have also one interesting trick
111
– (subtract last two digit number of your birth date(suppose my birth date is 1995 then i will take 95 and subtract from 111 i will get that i m how yrs old)
____
16

• Gail Jagla

Thank you very very much, in the end, after all days and even weeks of searching, I found something interesting. Yours!! Martha

some of the tips are really fantastic. I am going to share those with my school going kids. Thanks.

• macaulaytippins

Name

• shamsher khan mansoori

fantastic

• shreya

trick of 11 iz awsum…!!! m realy luvng it…

• Raman

Its awesome .The tricks are really cool & works. I have been helped a lot.

• akj

• aman

if I want to check if the given number abc is divisible by 9 .I check if the sum of the digits are divisible by 9 i.e. (a+b+c)/9

For example:
81/9=(8+1)/9
if it could be divided by 9 the whole number can be divided by 9

• anwar

2+2/2=?

• anwar

11*5=55
but 11*10= never comes 55

• Apurv goud

The trick for multiplying by 9 is good, but I always thought you’d look like an idiot in math class staring at your fingers, so my trick was simply…the answer will add up to 9, with the first digit being one less than your original multiplier…

ex – 7*9 = 63 (6 is one less than 7, and 6+3=9)

• ganesh pratap singh

very useful …. it realy works…

• splendour

i like this ones but please still send me some other ones on hw to division with multiplications most excpecially the ones the that in decimal places

• Knr

Maths

• rajan taneja

99*87=8613
first we sub 1 from 87 and in the end we compare with 100

• vijay

i like ….good job continue…………………………………………..

• ridhima srivastava

your tick is good or any tick give in e-mail

• saipavan

nice

• naseeb gill

awesome

• jayasree

super……..i like so much.

it is very usefull 4 compitative xms.

• saba fatima

2*1/9*1*2/9/2*1/3=/-1*1/2 i want solution for this

• very good and innovative tricks which generates intrest towards maths. Now i can say it is easy to learn maths.

• natasha

very interesting tricks…

simply ossom

thanks for shotcuts i like it

• dilip

when add the 1,3,5,7,9,11,13,15,17,19 will be 100.
how can find 50 when add any five numbers in these.

• Abhishek Anand

this is really a fantastic

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Name

• Dinkle

it is very very nice
but if i want to add my tricks then how to share

• ajay

superb tricks…

• Aastha Jain

It’s very good!!!!!!!!!!!…………

• Prash the king

there is another way 2 learn the table
9×1=09
write no. from 0 to 9 on one side and 9 to 0 on other
eg.09
18
27
36
45
seee this works

• Null

Math *Shudders*

• Momo Lanpok

I have gone through all ur very useful n valuable tricks n these will help me a lot 4 my exams.. would u plz send me some more if u have anymore triks 2 [email protected].. THANKS….!!!

• kunal taneja

which is the biggest number you can make with 3digits…….?
.
.
.
999 is wrong .
but,why?

9raise to the power 9raise to the power 9.

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I’m not absure

• balaji

any body know any maths projects.if you know send to [email protected]

• mathemagician

how to write table of 67 when you only know table of 7 :)
07
14
21
28
35
42
49
56
63
70
insert 3
insert 0
here we go, watch out for fun

0 6 7
1 3 4
2 0 1

2 6 8
3 3 5
4 0 2

469
536
603

670
those interested can know that it is original stuff and not copied from here and there….wanna more? check https://www.facebook.com/pages/Maths-fun-facts/311633308869763

• Vinod

hi… Sir….!
This is vinod kumar chilaka your site helped me a lot in learning arithmetic quickly and can u please provide the other topics of arithmetic like boats and streams , time and distance etc..,
Thank You Yours Vinod

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• riya

i feel better

• ragini

i love this mathmatical tricks thank u so much,u guys are doing a great job.

• ayman

i dont like math but i like the tip and tricks that you do

• masud

9% people increased to 1635. what is the before value of people?

• a decent fellow

it is good for the student to calculate things without calculater

• vagili thirumalesh

Bank Clerks , Arthamatic & Reasoning & marketing aptuited

• rupal

Al tricks r gud… bt i wnna knw abt ratio tricks..!!

• rajesh

i want mobile alart

• Ashish kumar

how to multiply two digit number with itself or another two digit number in mind.
like 64*64
step 1 take 60*60 = 3600
step 2 take 4*4 = 16
step 3 cross multiply 6*4 and 6*4. and then add both like 6*4=24 , 6*4=24,
24+24=48 and multiply by 10 = 480
step 4 add all steps 3600+16+480=4096

do little practice and u can do it in 20 sec

• uday

nice …….

• raghvendra

it,s very amezing

• Donyi Taga

Wow..it’s a gr8

• Trevor Shelton

I want to know what % incease 3.20 is on 61.20

• INDUCHOODAN T G

THESE ALL ARE KNOWN TRICKS……

• zeeshan

how to trick of rout

• sony

nice

• LATEEFAT

I THINK HAVE LEANRT ALOT TODAY THANKYOU

• pravin

it’s very nice work u have done keep it continue

• myluckstock

using this math trick make tough maths into easy

• Divya

Excellent math trick.. Found it too easy…

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• bipul

what will be squar of 625

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i like it

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i want this maths world. plzzzzzzzzzzzzzzz send me many books.

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• Divya purwar

these tricks really works well and help us to do our sums easily………..Enter your comment here.

hey i was needing quadratic formulas not this!

• samridhi

Nice…….it really help me a lot…..

• sindhu

thanks for giving all these.

• hemlata

its very easy to calculate and will save time of my child I like it
Thanks

• Nice and helpfull for me.

• rohit

u all are fools these all things are from vadic ganit from india.

• Amit kumar

new tricks will be updated soon
thanks …..
shortcut-maths.blogspot.com

• Vipul

Here is my trick ,mult of 12 =1.multiply by unit num by 2 now this num keep last. 2. other numbers by again 2
3.add this number in origanal number. e.g 12*52 step1)2*2=4 2)5*2=10 3)52 10=62 here is ans=624

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• Muhammed salman.k.v

EXAMPLES:
8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5

• ritishree

these all are cool but i wanted some square roots tricks9not the long division method)

• sabeeb.a.s

i am very like it.now i think maths is easy.Iam very thankful to you

Its a good method

• Harry Whitehouse

SQUARE NUMBERS

I’ve got a method, but it only works for numbers between 25 and 49,

So, if you have 48*48

And remember 25 as your first number to use, and 50 after that (I don’t know why it’s these numbers, it just is haha)

Take 25 from the number, 48 – 25 = 23

Then, take the number (48) away from 50, 50 – 48 = 2

Take this number and times it by it’s self: 2*2 = 04

Finally, put the numbers together, 23 and 04

48*48 = 2304.

BUT for numbers above 49, (50*50 is obviously 2500) the method changes

So, if you were to have, for instance 87*87, and follow the steps at the top,

87 – 25 = 62

50 – 87 = -37 BUT flip this, so it’s positive, (37)

Then using the previous method, (for numbers under 50) square the number

37*37 is 1369

So we put the numbers together, HOWEVER

because 2 digit numbers squared can only be 4 digits long (99*99 is 9801) this is where it gets tricky

So, we have 62, from 87 – 25

And 1369 from 37*37

The 62 must add to  the first two numbers of the 1369

So, 62 13 = 75, then the rest of the numbers (69) adds on the end, 7569

87*87 = 7569

ALWAYS REMEMBER that if the number being squared ends in 0, it’s just the first number, times by it’s self 2 zeroes added to the end ie 70*70 = 4900, 7*7= 49
130*130= 16900, 13*13 = 169

I only tried this up to 199 but the sum just becomes too long, however I assume it could go on ad infinitum :)

-Harry W

[email protected]

• dsp

you please tell me short for non verbal reasoning

• Photius

Nice collection! The comments also have some great mental math tricks. I’ll definitely link here from Ars Calcula (http://arscalcula.com/), where I’m trying to compile mental computation methods.

• unkown..;-/

Great tricks
useful for exams
it saves time

• sandhya kahar

very good tricks .I like it

• Jay

finding of percent was good

• You guys are making fool its totally waste of time to visit this site for any thing helpful

• Just a fool will like these tricks
Solve this with the trick shown here.
Find 7% of 9833

• sachin

it’s fantastic it realy makes relible to make calculation

• arunabh kumar bhattacharjee

i have got a simple trick in case of multiplication of some large nos with 25. divide the number given by 4 Eg 2223242526 * 25. here divide the number(2223242526) by 4. dividing by 4 gives 555810631. & it leaves a remainder 2 . after multiplying the no by 4, if it leaves remainder 0,then put 00 at the end, if it leaves remainder 1, put 25 at the end, if it leaves remainder 2,put 50 at the end & if it leaves remainder 3, put 75 at the end . Here after dividing by 4 it leaves remainder 2, so put 50 at the end Therefore the answer is 55581063150

• Captain

I love this,Thanks so much

• Reciprocal Teaching

I am no longer sure the place you are getting your info, however great topic. I needs to spend a while finding out more or figuring out more. Thanks for wonderful information I was looking for this info for my mission.

• zodiac x7 quattro

Name

• karnail

how calculate by this trick 18*12=?
& 13*18=?

• amit sharma

extremly please send sort tricks my email ad. level of claas 11 & 12 thank you

• atul

g00d tricks

• sarah

how many times can you make a hundred with maths

• NIKUNJ

I like these all tricks really…..please suggest me about other maths tricks like its…..

• vikram

very nice

• R.J.

CAN U SHOW A TRICK TO MULTIPLY OR DIVIDE BY IT…???????

• R.J.

I meant with the number 314

• twinkle

its gd infact its v gd

• Nic tricks …
Maths iz alwayz an easy n scoring subject … need iz to give ur concentration … ;)

• ishan

respected sir,
Please share the short cut method of cube of numbers….

Name

• Vandana Thakur

For percentage there is one more easier method :

example1:- 8% of 250 = ?
1% of 250 is 2.5
Therefore, 8% will be 2.5*8= 20

example2:- 5% of 300 = ?

1% of 300 is 3
Therefore, 5% will be 3*5 = 15.

• Ravi

To find squr any three digit no.
Exg.squar of 98=100-2 02*2
=98 04=9804

• nic

Not sure why the ‘Quick Squares’ trick doesn’t work when there’s a 1 in in the tens place.

Ex) 15^2 ==> (1x(1+1) = 2 ==> 2 & 15 ==> 215 ? 15^2. This is false b/c 15^2 = 225.

Where did I go wrong?

• deepak

i have read this tricks but i dont like

• Rashika

i like this site as it helped me in completing my maths project in an easy an clear way!!everything was legible.

• raman arora

i like of your magic…..rule……….if you have more magic plz send to my id …………thannxxxxxxxxxxx

• babu

23*2=46

• patil bm

We all know the trick when multiplying by ten – add 0 to the end of the number, but did you know there is an equally easy trick for multiplying a two digit number by 22? This is it:

Take the original number and multiply by 2 and imagine a space between the two digits (in this example we will use 31:
31*2=62
6_2

Now add the two numbers together and put them in the middle:

6_(6+2)_2

That is it – you have the answer: 582.

If the numbers in the middle add up to a 2 digit number, just insert the second number and add 1 to the first:
Eg. 42?
42*2=84
8_(8+4)_4

(8+1)_2_4

9_2_4

924 – It works every time.

• Tgese tips really helped I don’t think I will struggle any more thanx!!!

• Kalimah Mariko

I absolutely love it, It was truly helpful , Al Hamdulillah

• Vasantha Kumar

It is useful 2 me

• ritik sharma

multiply 100 – 110 for example multiply 103*104 first multiply last two no 3*4=12 are last no then add 103+4 107 then your ans is 10712

• vishwas

there r very less no. of tricks that r useful, may u send me other important tricks.

• anshuman sahu vedant sahu

must hai! boss

• kumarg

good tips

• Yamini singh

what a wonderful tricks. You know if i study tthese i will surely good in maths

• SHAH VIDHI

every two digit number are multyply ,i.e
.1} 19*11= 209.
bt before 19 its 18 and before 11 it is the 10 , so multyply by
2} 18*10=180
THAN : Minus the 1 & 2 step , answer will always :- 29
CHECK THE OTHER 2 DIGIT NUMBER…..

• SHAH VIDHI

every two digit number are multyply ,i.e
.1} 19*11= 209.
bt before 19 its 18 and before 11 it is the 10 , so multyply by
2} 18*10=180
THAN : Minus the 1 & 2 step , answer will always :- 29
CHECK THE OTHER 2 DIGIT NUMBER…

• SHAH VIDHI

MATHS MAGIC…:-p

• SHAH VIDHI

Multyplay Two same number i.e.
1} 18*18=324
2}12*12=144
so, whenever you do like dis always the last number is : see the
1st step- 8*8=64 so last number is 4
2nd step-2*2=4
so last number is always which was get our 1 and 2 step multyplay…..

• hareesh

nice tricks i will follow

• krishan kumar

i like this tricks very much so please forward some more another ticks

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• nanichowdary

it is very useful for the kids

• Latif

I like it
if you have time, please visit at mainmatematika.blogspot.com
I ask for help to correct…

• best proxies

Its like you read my mind! You appear to understand so much about this, such as you wrote the e book in it or something. I think that you simply can do with some % to force the message house a little bit, but other than that, this is wonderful blog. An excellent read. I will definitely be back.

• farshid.net

???? ???? ???? ?? ??? ? ?????? 9 ???-???999
999*999=?
?? ????? ??? ???? 9 ????????-??? ?? 8 ????????-??? ?? ????? 9??? ?????? ??? 0 ???????? ? ?? ??? 1 ????????-
998001

• vah

• Vijaya

How To Solve 4444=10 Any Symbol use

• Ganeshram

Maths tricks is awesome !!! Enjoyed maths for first time

• bar

Tremendous things here. I am very glad to look your article. Thanks a lot and I am having a look forward to contact you. Will you kindly drop me a e-mail?

• prathamesh

nice tricks yar awesome but confusing

• akhila.r.pillai

thank u very much.

• pooja

nice

• RAJU

2*2=4

• Morris

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Morris

• Ravikant

thats a fantastic trick. all tricks has been got into my mind.

• Ravikant

i couldn’t understand about the trick – Multiplying by 3

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