To find Square root,

we subtract consecutive odd numbers from number till we obtain 0.

Square root = Total numbers subtracted.

Let’s take an example

Suppose we need to find

√81

####
**
Square root of
**
**
√81
**

- 81 − 1 = 80
- 80 − 3 = 77
- 77 − 5 = 72
- 72 − 7 = 65
- 65 − 9 = 56
- 56 − 11 = 45
- 45 − 13 = 32
- 32 − 15 = 17
- 17 − 17 = 0

Since, after subtracting 9 numbers, we obtained 0.

∴
**
√
**
**
81
**
**
**
**
=
**
**
9
**

####
**
Square root of
**
**
√81
**

- 81 − 1 = 80
- 80 − 3 = 77
- 77 − 5 = 72
- 72 − 7 = 65
- 65 − 9 = 56
- 56 − 11 = 45
- 45 − 13 = 32
- 32 − 15 = 17
- 17 − 17 = 0

But, if we take a big number, like 729.

How would we find square root?

We do it by prime factorization (link)