What does it mean to say that a number is a perfect square? give on example of number that is a perfect square and of one that is not. explain your examples.

A number called a perfect square means that the number has an exact squared root. In other words, the number has an squared power, which is exact.

Other way to see this, it's taking natural number 1, 2, 3, 4... then, applying the squared power to each one, the results of each squared power is what we call a perfect square. For example, 1, 4, 9, 16, 25, 36,..., are all perfect square, because they are the result of a squared power: