Principle objective of this article is to Define and Discuss on Functions. Here explain Functions in mathematical point of view with examples. A function is defined as a set of ordered pairs ( x, y), such that for each first ingredient x, there corresponds one and only one second element y. The set of first elements is named the domain of the particular function, while the pair of second elements is called the number of the function. The domain variable is called the independent variable, and the range variable is called the dependent variable.