Since we are adding fractions, we need common denominators.
First we should factor both denominators.
After we factor both denominators, we see that both fractions can be reduced.
In this case we find ourselves with common denominators after simply reducing both fractions. At this point we need only add the tops.
In this case we were very lucky that we had common denominators as soon as we reduced the fractions, but it can happen, and is another reason for factoring all of the denominators first.