This topic is in the 'Relations and Functions' section. As you learn more and more Algebra, you'll be faced with a vocabulary challenge because there will be new words that you have learn. Relation and Function are two of those key words that you have to know. Think of relations as machines that take in some numbers or variables, follow a special pattern, and spit out new numbers or variables based on that special pattern. Functions are special versions of these machines, and you'll learn more about the specifics in some of the example tutorials in this section.