Parameters are variables or arguments that are passed to other functions and methods to be used. They are especially useful so that you only have to make one method that takes a parameter instead of making many methods that do the same task. On example I can think of is you could make a method called calculate that can add subtract divide and multiply.This method would take 3 parameters one to determine what mathmatical operation you want to do say a string and the other two would the numbers you want to use in your problem.
Here is that world in action:
example2.a2w