What are the different methods in Calculus?

In our junior classes we were taught regarding Addition and subtraction which were only applicable to discrete function for example 1+2+3=6 and 5-2=3, but what about the numbers that exist between 1 and 2 i.e 1.1, 1.2....n so on. Therefore in our senior classess we talk about continous function which can only be solved through calculus which has basically two methods i.e differentiation ( also called subtraction for continous function) and integration (also called addition for continous function). In differentiation we convert any bigger function/unit into smaller function while in case of integration, a smaller function or a smaller unit is converted to bigger unit or function. Integration and differentiation are opposite to each other. read less