Which of the following are examples of perfect square numbers?

The selection of 4, 9, 16, and 25 as perfect square numbers is correct because these numbers can be expressed as the square of whole numbers. Specifically, 4 is the square of 2 (2 x 2), 9 is the square of 3 (3 x 3), 16 is the square of 4 (4 x 4), and 25 is the square of 5 (5 x 5). Perfect square numbers are integers that result from multiplying an integer by itself.

In contrast, the other options consist of numbers that do not meet the criteria for perfect square numbers. The second option includes prime numbers (2, 3, 5, 7), which cannot be expressed as the square of an integer. The third option presents a set of even numbers that are not squares of integers (10, 12, 14, 18). The last option lists numbers that also do not fulfill the requirements of being perfect squares, as they cannot be represented as an integer multiplied by itself. Understanding the definition of perfect squares helps distinguish them from other types of numbers.