How do you find the square root of 31?

Answer 1

First the closest square is 52=25 so the first digit is 5

Then you write two 0 at the right of 31 -> 3100 and try to find the closest square between 50 and 59 (5 is the first digit found)

The closest square to 3100 is 55, 552=3025, 562=3136, so the second digit is 5 and one gets 55

Now with 310000 and a number between 550 and 559, the closest square is

5562=309136, the third digit is 6 and so on....

So sqrt(31)=5.56....