How do you make denominators the same when adding fractions?

Answer 1

Think of it this way. In order NOT to change the values of the fractions, you have to be careful to multiply any fractions you are working with by 1. The value 1 can look very different from one; it can be 2/2, 3/3, 4/4, etc. I want to add 1/2 and 2/3. First, I wonder if the smaller denominator 2 is a factor of the larger denominator, 3. It isn't. So, I can multiply the first fraction by 3/3 (which equals 1), and multiply the second fraction by 2/2 (which also equals 1). This will give me the fractions 3/6 and 4/6, which are easy enough to add. If I want to add 1/2 and 3/8, I wonder if the smaller denominator 2 is a factor of the larger denominator, 8. It is. So if I multiply the first fraction by 4/4 (which equals 1) I end up with 4/8 and 3/8, and these are easy enough to add. It might also be possibe to bring the denominators down to the value of smaller factor that is common to each fraction, but values of the numerators may get messy. for example, 3/4 + 8/16 could become 3/4 + 2/4. But if your fractions are 3/4 + 11/16, this will be a little harder to do. I would do 12/16 + 11/16.