What does " inverse pairs undo each other"?

Question

I'm having difficulting understanding the concept of inverse
and i dont know what inverse pairs undo each other means?

Answer 1

If you are speaking of functions and their inverses, then it simply means that the composition of a function and its inverse evaluated at x, f(f^-1(x)), is just x, as long as f^-1(x) lies in the domain of f. Thus, because y = e^x and y = ln (x) are functional inverses, ln (e^x) = x, for example.

Answer 2

The inverse (or reciprocal) of a number a is 1/a. The inverse of a fraction a/b = 1/(a/b) = b/a

They undo each other because:

(1/a)*a = 1
(a/b)*(b/a) = 1

Ex.
4 * 1/4 = 1
4/3 * 3/4 = 1
624/849 * 849/624 = 1