Squaring a number that ends in 50 is very easy.

This method can be applied to any number which is onn either direction of 50, i.e. 55, 52, 47, …., 59 and so on.

Let’s explore this with an example:

542 52+4 / 42 29 / 16 → 2916

For numbers greater than 50

The result is comprised of two “parts”

The bottom “part” is always the bottom digit squared

The top “part” is the top digit squared plus the bottom digit

532 25+3 / 9 28 / 9 → 2809

 For numbers less than 50

 The result is comprised of two “parts”

The bottom “part” is always the bar of the bottom digit squared

The top “part” is the top digit squared minus

the bar of the bottom digit

482 25-2 / 22 23 / 4 → 2304

462 25-4 / 16 21 / 16 → 2116