# In this Section:

In this section, we learn how to add and subtract rational expressions. This process is exactly the same as when we added and subtracted fractions.
When there’s a common denominator, we add or subtract the numerators of our rational expressions and place this over the common denominator. Once this is done, we simplify and report our answer.
When there is not a common denominator, we first find the LCD for our rational expressions. Then we rewrite each rational expression as an equivalent rational expression where the LCD is its denominator.
We can then add or subtract numerators and place the result over the common denominator. Lastly, make sure that the reported answer is simplified.