Additive Inverse

In mathematics, the additive inverse of an element x, written as minus x, is the element that yields the additive identity, most often zero, when added to x. In elementary mathematics it is usually called the opposite number or the negative of a value, and the unary operation of arithmetic negation is closely tied to subtraction and plays an essential role in solving algebraic equations. Not every mathematical set that supports addition contains additive inverses for all of its elements; the natural numbers are a key example of a set with no additive inverses within the set itself.