In mathematics, value may refer to several, strongly related notions.
In elementary mathematics, this is most often a number – for example, a real number such as π or an integer such as 42.
For example, if the function f is defined by f(x) = 2x2 – 3x + 1, then assigning the value 3 to its argument x yields the function value 10, since f(3) = 2·32 – 3·3 + 1 = 10.
If the variable, expression or function only assumes real values, it is called real-valued.
Likewise, a complex-valued variable, expression or function only assumes complex values.