Step-by-step explanation:
come on ! divide top and bottom by factors you can easily see. and then keep going, until you cannot find any factor anymore.
with numbers like 75 and 90 we see one thing immediately : they are divisible by 5.
so,
75/90 = 15/18
aha ! and 15 and 18 are divisible by 3.
15/18 = 5/6
and that's it.
