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