This chapter is an introduction for a branch called calculus. Calculus is that branch of mathematics which is associated with the study of change in the value of functions as the points of domain change. This chapter will help us to understand differentiation and integration which we study in next class. Topics of this chapter are limit of function introduced as rate of change of distance function and its geometric meaning, definition of derivative, derivatives of sum, difference product and quotient of functions, derivatives of polynomial and trigonometric functions.