MATH TRICKS

MATH TRICKS

Math Trick #1:

How to multiply a two digit number by 11:

For example, 43×11. Take the original number and imagine a space between the two digits:

4_3

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

4_(4+3)_3 which is the same as 4_7_3

The answer… 473

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

For example, 67×11

6_(6+7)_7

(6+1)_3_7 which is the same as 7_3_7

The answer… 737

Math Trick #2:

How to square a two digit number ending in 5

If you need to square a two digit number ending in 5, multiply the first digit by itself + 1, and put 25 on the end.

For example, 65^2 (which can be written as 65×65)

6x(6+1) or 6×7 = 42

Put a 25 on the end of it…

The answer… 4225

Math Trick #3:

How to multiply big numbers by 5

Take any number, then divide it by 2. Then…

If the result is whole (that is, theres’s no remainder), add a 0 at the end.

If it is not whole, ignore the remainder and add a 5 at the end of the number.

For example, 4252×5 = (4252/2) and add a 5 or 0 to the end of the number

4252/2 = 2126 (it’s a whole number so add a 0 to the end)

The answer… 21260

Here’s another example: 8667×5

Divide the number by two: 4333.5 (there’s a remainder so add 5 to the end)

The answer… 43335