An inverse operation is one that "un-does" an operation.

If you perform the operation on some value or variable, the inverse operation performed on that result will give you back the original value or variable. In other words, the two operations together result in the identity element for that operation.

One example is below:

The additive inverse of a number is its "opposite". If I add 2, for example, then add its opposite, -2, the result is the same as adding 0, the additive identity element.

x + 2 - 2 = x + 0 = x