How To: Calculate Faster Than a Calculator

Calculate Faster Than a Calculator

How to Calculate Faster Than a Calculator

When you need to crunch numbers quickly—and I mean really quickly—there's a cool method you can use to multiply 2 numbers together in just a few seconds.

This is a great for impressing your math teacher or peers, or just a cool party trick (depending on your crowd).

For the first example, let's calculate the following:

Start by taking the first digit of the first number (2 for 24) and multiplying that by the number directly ahead of it, which will give you the first digit(s) of the answer.

24 x 26 =
2 (first digit in first number) x 3 (one digit higher) = 6

6 is our first digit in the answer.

Now take the second digit of the first number (4 for 24) and multiple that by the second digit of the second number (6 for 26), which will give you the remaining digits of the answer.

24 x 26 = 6__
4 (second digit in first number) x 6 (second digit in second number) = 24

2 and 4 are the the last digits of the answer.

So, 24 x 29 = 624

Voila!! You're done. But wait, there's more.

A Few Restrictions

If you thought this method was too good to be true, well, you're right. There are a few restrictions, or caveats, that must be adhered to:

  • the first digits of both numbers must be the same
  • the last digit of both numbers must equal 10

If you look at the example above, the first digit in each number (24, 26) is 2, and the last digits in each (4, 6) equals 10. Let's do a few more examples to hit this point home.

37 x 33

3 (first digit in first number) x 4 (one digit higher) = 12

1 and 2 are our first digits in the answer.

7 (second digit in first number) x 3 (second digit in second number) = 21

2 and 1 are the the last digits of the answer.

So, 37 x 33 = 1221

122 x 128

12 (first digits in first number) x 13 (one digit higher) = 156

1, 5, and 6 are our first digits in the answer.

2 (second digit in first number) x 8 (second digit in second number) = 16

1 and 6 are the the last digits of the answer.

So, 122 x 128 = 15616

For a more visual guide, check out the video below from Roger73026:

Cover image via Roger73026



try with : 10 X 10 ???
84 X 88 ???

the last digits have to equal 10


well to solve the theory's problem... you can do it as (15-5)(15-5)=(15X15)-(15X5)-(15X5)-(5)^2 and then use the relation in 15X15... that's a general solution to have last digits adding to 10 with calibrating them to 5, anyone has a much shorter faster solution?

yea watch the whole video it has 2 meet 2 criterea... the first digit on the first number has to be the same as the first digit on the second.. and the 2 second digits have to add to 10... whcih all in all kinda makes this treick useless

Very good!

ok!!!!!!!!!!!!!!!!not too

well if ur smart enough to realize that then i guess you dont need this tip then do u? theres always exceptions to the rules; "i before e except after c?" that seems kinda weird doesn't it?

It has its limits Just like finding out the answer to any number multiplied by nine between one and nine. Where you take the number before the number you're trying to multiply with nine then find out what number added to it will equal nine then put the two numbers together and that is your answer. An example is 9 * 7 = 63 The 6 from 63 comes before the 7 from 9 * 7 and 3 added to the 6 will equal 9.

it kink of sucks because it would be a coincidence to run in to such a math question

yah you can teach this to children for trick purposes

try this:condition :two no. are of even dist.
ex:37*33 mid value =35
sq. 35 = 1225
37*33 = sq.35-dist b/w ywo digit i.e.4 = 1221

2 much of a coincidence needed 2 b of any use

pretty cool!

its good to know some tricks

pretty cool

Never thought i'd say this to a guy, but. I love ya man!

26 x26
46 x 47
98 x 97
Please remove this video else you may lend someone in trouble

hello, can i get any soft ware for this, like abacus solutions

hello can i get maths trick for download like this

how to get by this 1415,

very very cool!!!!!!!!!!!!!!!!!!!

smart and when I did it it didn't work!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

very very intersesting and learning

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