Integrals in calculus are also called integrations, which is the process of adding pieces together to find the whole. On the other hand, integration is often used to find areas, volumes, central points, and many other useful things that we can't find with simple math formulas, like the area of a square or the volume of a cylinder. If you know the problem's derivative, you can turn it around to find the problem's integral. To write an integral down, we need notation, which is a symbol for an integral that we put in front of the function whose integral we want to find. This symbol is also called the Integrand, and we end with dx. When writing an integration called "constant integration," there is also a "Plus C."