it is better to reffer to a color wheel. the colors next to each other are the complemetary colors and the colors opposite each other are opposite colors to each other.
Let's start with what colors have complementsred and greenblue and orangeyellow and purpleone of the colors in the pairs is a primary (where no colors can be mixed to make that color) and the other...
It's a complicated answer. The following content is according to the wikipedia page linked: 1. According to color theory, mixing complementary colors produces a neutral color (white, black or gray)....