An easy way to solve this problem is by finding the same denominators for both of the fractions. You can do this by multiplying 9 times 6 equals 54 and what you do to the bottom you must do to the top. So 5×6=30 and 1×9=9 13 30/54- 8 9/54 = 5 21/54 and then if you can simplify you do.