You may know some of the tricks listed below, but it still nice to refresh your memory to do some quick calculation in your head. Some tricks such as the 11 tricks is very well known :

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.

But don’t forget to practice this tricks in your head, ok?

10 Easy Arithmetic Tricks [via Listverse]

Tags: mathematic, tricks

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