Squaring a number that ends in 5 is very easy.

This method can be applied to any number of the form: 15, 25, 35, …., 95, 105, 285, …. and so on.

Sutras:

- By One More Than the One Before

Let’s explore this with an example:

35^{2} ** → **3•4 / 25

**12 / 25**

*→*

*→ 1225**The result is comprised of two “parts”. *

*The bottom “part” is always 25. *

*The top “part” is n(n+1).*

More examples as below:

75^{2} ** → **7•8 / 25

**56 / 25**

*→*

*→ 5625*45^{2} ** → **4•5 / 25

**20 / 25**

*→*

*→ 2025*95^{2} ** → **9•10 / 25

**90 / 25**

*→*

*→ 9025*115^{2} ** → **11•12 / 25

**132 / 25**

*→*

*→ 13225*