The word calculus means “pebble” in Latin.
Pythagoreans used pebbles, lined up to form various shapes, to represent numbers.
The earliest ideas that led to integral calculus can be found in the Egyptian Moscow papyrus, and described calculations of volumes and areas, one goal of integral calculus.
Historically, calculus was known as “infinitesimal calculus”.
Archimedes worked on the method of exhaustion, inventing heuristics which resemble the methods of integral calculus.
Calculus has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem of calculus.
Calculus is used in physics and all concepts in classical mechanics and electromagnetism are interrelated through calculus.