What is a square number?

A square number is the result of multiplying a number by itself. For example, 4 is a square number because it is 2 x 2, and 9 is a square number as it is 3 x 3. This concept is named because the numbers represent the area of a square with sides of a certain length. Interestingly, square numbers follow a pattern (1, 4, 9, 16, 25, ...), and the difference between consecutive square numbers increases as you go higher (the difference between 1 and 4 is 3, between 4 and 9 is 5, and so on, always increasing by 2). Both positive and negative numbers can produce square numbers, but square numbers are always non-negative.