ok so we need the bottom number to be the same to compare remember that when x=x, x/x=1 so 9/9=1 if you multiply anything by 1 it is the same to change the bottom number you have the multipy the whole fraction by 1
so we have 7/8 and 8/9 we need to make 8 and 9 into a common number jus muitply 8 by 9 and 9 by 8 so 7/8 times 9/9=63/72 8/9 times 8/8=64/72
