The Arithmetic field of study covers any activity that studies mathematics in order to manifest the material. The Calculus field of study covers any activity that studies Calculus in order to manifest the material. Calculus is a branch of mathematics that includes the study of Limits, Derivatives, Integrals, and Infinite Series, and constitutes a major part of modern university education. Historically, it was sometimes referred to as "the calculus of infinitesimals", but that usage is seldom seen today. Most basically, calculus is the study of change, in the same way that geometry is the study of space.