How is doing operations (adding, subtracting, multiplying, and dividing) with rational expressions similar to or different from doing operations with fractions?

Answer 1

You have both numerators and denominators to deal with. Very specific new rules apply. You need common denominators to add and subtract, and the operations are performed on the numerators only. In multiplication of two fractions, both numerators and denominators are multiplied separately. When dividing by a/b, multiply by b/a instead.