Additive inverse

The additive inverse of a number is a number that is the same distance from 0 on the number line, but in the opposite direction.

Examples
+3 + -3 = 0
In the example, +3 and -3 are additive inverses or opposites.
-3 is the additive inverse, or opposite, of +3.
+3 is the additive inverse, or opposite, of -3.

See also additive inverse property, opposite of a number.