## Math Tricks

By**admin**

## Fast way to square numbers ending in 5

**Quick Square:**

If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. Multiply 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

## The secret of the number 9 (Multiplying by 9)

**The fast way to multiply by 11**

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 26:

2_6

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

2_(2+6)_6

That is it – you have the answer: 286

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.

Practice it on paper and there you go – amazing your friends!