Калькулус is a branch of mathematics that focuses on the study of change and motion. It involves concepts such as limits, derivatives, and integrals, which help in understanding how quantities vary with one another. The two main types of калькулус are differential calculus and integral calculus. Differential calculus deals with the rate of change of functions, while integral calculus focuses on the accumulation of quantities. Together, they provide powerful tools for solving problems in physics, engineering, economics, and many other fields.