How to use multiple methods in C#?

Seems to me that before you can learn to write methods, you should learn to write C functions.
Either that, or I don't understand what you're trying to do, and what you mean by "call back".

That's how my teacher phrases it, but I barely understand him so I can't quiet say what it means either. Is there another way of saying it?
The project I am doing is an exercise from my text book and it's phrased like this:

Write a program that allows the user to enter two integers. Write separate methods that will produce the sum, product, average, and squared result of the values. Call the results with both values entered.