Calculus is a branch of mathematics that describes continuous change.

There are two different types of calculus. Differential calculus divides (differentiates) things into small (different) pieces, and tells us how they change from one moment to the next, while integral calculus joins (integrates) the small pieces together, and tells us how much of something is made, overall, by a series of changes. Calculus is used in many different sciences such as physics, astronomy, biology, engineering, economics, medicine and sociology.