What is an inverse operation?

An inverse operation is an operation that reverses the effect of the original operation. For example, addition and subtraction are inverse operations. 2 add 5 is 7, subtract 5 is 2. The subtraction of 5 reversed the effect of adding 5. Multiplication and division are also inverse operations.

Two functions f and g are inverse if f(g(x)) = g(f(x)) = x.