In maths, the fundamental concepts of calculus include limits, differential calculus, integral calculus, function theory (single and multi variables) or multivariate calculus. Differential calculus involves differentiation of functions that measures the rate of change of quantities. Integral calculus deals with integration of functions which is opposite of differentiation. Also, it is used to find the area under curves and volume of solids in three dimensional area. The two primary operations of calculus are differentiation and integration. Both of these are based on the concept of a limit, which is an infinite (or infinitesimal) approximation.