Anytime you square an integer, the result is a perfect square! The numbers 4, 9, 16, and 25 are just a few perfect squares, but there are infinitely more! Check out this tutorial, and then see if you can find some more perfect squares!
Taking the square root of a perfect square always gives you an integer. This tutorial shows you how to take the square root of 36. When you finish watching this tutorial, try taking the square root of other perfect squares like 4, 9, 25, and 144.