relation is a relationship between elements of the same set or two different sets. We can also reason it as a relation between the ordered pairs or the relation is between the x-values and y-values of ordered pairs. The set of all x-values is called the domain, and the set of all y-values is called the range. The concepts of this lesson are used in discrete math and predicate calculus. Any student who complete this lesson and scores more than 70% on the final quiz will get a Certificate of Completion.