Range is a term used in different branches of mathematics including algebra, set theory and probability theory. It is usually first encountered in algebra in the study of functions, and is typically defined as the set of all values attained by a given function throughout its domain. One can think of a function, denoted by the letter f, as a rule that takes a given value and yields another, unique value. Within algebra this rule takes the form of an algebraic expression. For instance, the expression "x²" transforms the number values of "x" into another set of number values. This rule can be denoted by the equation y = x². In general, a function f can be thought of as consisting of all the values that x possesses, as well as all the values that y possesses.

A function has a domain and a range. The domain is the...