#### Answer

Opposites or additive inverses are two numbers that have opposite signs but have the same absolute value. Their sum is equal to zero.
(refer to the step-by-step part below for an example)

#### Work Step by Step

Opposites or additive inverses are two numbers that have opposite signs but have the same absolute value. Their sum is equal to zero.
Example:
$-4$ and $4$ have opposite signs but have the same absolute value of 4.
Thus,
$-4 + 4 = 0$