There are many ways. \(\frac{9}{18}\) is actually the same as \(\frac{1}{2}\) so anything you do just has to have a numerator exactly half as the denominator. So one that would work is \(\frac{18}{36}\) I just doubled both numbers. Other ones would be \(\frac{5}{10} and \frac{6}{12}\) all of which the numerator is exactly half the denominator.
