Find the number of three digit perfect squares which has a non zero perfect square unit digit

Explanation

Let the square root of a three digit perfect squar be x then `10le x le31` (since `32^(2)` is a digit number and 92 is a 2 digit number)
Single digit perfect squres are 1,4 and 9
The squares which end with 1 or 4 or 9 are `11^(2),12^(2),13^(2),17^(2),18^(2),19^(2),21^(2),22^(2),23^(2),27^(2),28^(2),29^(2)and 31^(2)`
There are 13 such number