Write all numbers from 400 to 425 which end in 2, 3, 7 or 8. Check if any of these is a perfect square.

Consider all integers from –10 to 5, and square each of them. How many distinct numbers do you get?

Write the digit in unit’s place when the following number are squared:

4, 5, 9, 24, 17, 76, 34, 52, 33, 2319, 18, 3458, 3453.

Find the sum of the digits of (111111111)².

Suppose x² + y² = z².

(i) if x = 4 and y = 3, find z;

(ii) if x = 5 and z = 13, find y;

(iii) if y = 15 and z = 17, find x.