An ordered pair is a pair of numbers which are used to locate the point on a coordinate plane. The set of all possible ordered pairs with first element and second element y is called Cartesian Product. This note contains information about ordered pairs, cartesian product and its diagrammatic representation.

A relation between two sets is a collection of ordered pairs containing one object from each set. Any subset of A × B is called a relation from A to B. A relation from A to B is denoted by R. A relation from A is called a relation on A. This note has information about relation and its representation.