This tutorial is the first among the series of tutorials on Mathematical shortcuts. In this tutorial, we are going to learn how to obtain the square of a number ending with 5.

For example, numbers such as 25, 35, 95, 115 etc. Lets say, we want to calculate the square of 25.

The entire steps are illustrated in the following figure.

**Step 1 :** Break the number such that 5 i s on the right and the rest of the digit ( i.e., 2 in this case) is on the left.

**Step 2 :** Obtain the square of 5 which is 25. This forms the RHS part of the answer.

**Step 3 :** Take the rest of the digit on the left and multiply by the next higher digit that follows it. In our case, we need to multiply 2 by 3 which gives us 6 which forms the first part of the answer.

So, the final answer is 625.

Similarly, can you compute mentally compute 115^{2 }?

**Exercise :** can you mentally obtain the squares of :

- 125
- 135
- 85
- 95

If you have any doubts regarding this tutorial, please leave a comment or contact me. I would be glad to help.

it’s great. thank you sir

I am glad you liked it. Thank you so much. Share it with your friends who might find it useful.

its awesome sir thankx alot…

its very good and helpfull,thankx a lot sir.

thankx a lot sir its very useful

I am glad you liked it

Sir,

It’s really help-full topic but… when apply this rule

in 625 it doesn’t give me actual result..

let me clarify.

625=6(6+1)|25*25

=42625

but actual ans is 390625

The method is to split the number in two parts : a unit digit and the remaining number ,here 625

62 and 5

62*63=3906

5*5=25

so answer is 390625

Otherwise use the trick ::

square of a number ending in 25