Much like a square, a cube is when you multiply a real or complex number by twice itself (making a total of three numbers). Mathematicians express the cube of a number using the superscript 3; or, for example, 2³, or 2 × 2 × 2. Unlike a square of a number, the cube of a number will not always be positive, such as -3 × -3 × -3, which equals -9.

A cube root is a number that when multiplied by itself two more times has the product of s, in which t³ = s. For example, the cube root of 125 (s) is 5 (t), or written as ; the cube root of -125 is -5.