Basic FOIL on 2-by-2 parentheses

In this video we'll learn the most common FOIL situation, multiplying parentheses that each have two terms in them (a.k.a. binomials). Most students don't have too much trouble with the concept of FOIL; the most common mistake is forgetting one of the terms. First, Outside, Inside, Last is one way not to forget any terms, but I'll also show you my favorite graphical technique: drawing rainbows over and under to keep track.