Inverse operations are those that “undo” another operation. In particular, subtraction is the inverse of addition because a + b - b = a; division is also the inverse operation to multiplication.

The inverse of a number can be expressed as follows: The additive inverse of a real or complex number a is the number that, when added to a, equals 0. In multiplication, the multiplicative inverse of a is the number that, when multiplied by a, equals 1.