Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematical study of continuous change, in the same way that geometry is the study of shape and algebra is the study of generalizations of arithmetic operations.
In Simple words, Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series.
Limits and continuity.
Derivatives: definition and basic rules.
Derivatives: chain rule and other advanced topics.
Applications of derivatives.
Analyzing functions.
Integrals.
Differential equations.