How do you subtract fractrions?

Answer 1

First, to subtract fractions, you need to make sure that the both have a common denominator. By this, I mean that they need to have the same number on the bottom of the fraction. If they are not the same, you need to multiply.

Say you had this problem:

4/5 - 1/3

You will notice they don't have a common denominator. To make sure that the bottom is the same number, multiply 4/5 by 3 and 1/3 by 5. When you multiply, you do this to both the top and the bottom number. The problem now looks like this:

12/15 - 5/15

Now you're ready to subtract! All you have to do is subtract the top numbers, and keep the bottom ones the same. So:

4/5 - 1/3 = 7/15