Question

Find the number of digits in the square root of the following number (without any calculation).

$390625$

Answer 1

If there are even number of digits in a square of a number then the square root has $\frac{n}{2}$ digits, if there are odd number of digits in a square of a number then the square root has $\frac{n+1}{2}$ digits
In this case, there are $6$ digits in $390625$ hence, the square root has $3$ digits