In mathematics, a multiple is the product of an arbitrary set of numbers and a integer. The multiple of a number \(n\) by the number \(x\) is the number \(m=nx\). The multiple root of an equation is a root with a multiplicity greater than or equal to 2; the multiple point of a curve, surface, or variety is a point with a multiplicity of points of intersection greater than or equal to 2.

Thus, every non-zero number has infinite multiples, and the result of any multiplication is a multiple of the two factors. In set theory, the set of multiples of a nonzero integer is an infinite set of numbers.

In metrology, a multiple of a unit of measure is a derived unit whose value is a multiple of a reference unit.