This document provides an introduction to calculus, including its definition, classification, and key concepts. Calculus is the branch of mathematics dealing with finding derivatives and integrals of functions, based on infinitesimal differences. It has two main types: differential calculus concerns rates of change, while integral calculus involves the theory and applications of integrals and integration, such as determining lengths, areas, and volumes. The document defines differentiation as finding derivatives and integration as evaluating indefinite or definite integrals. It provides formulas and examples of differentiation and integration.