Algorithms that computers work on deal with numbers—in fact the module Types will discuss the concept of "Everything is a number," which is a key principle in programming. Computers can only compute on numbers; however, this course will also illustrate how we can represent a variety of useful things (letters, words, images, videos, sound, etc.) as numbers so that computers can compute on them. As a simple example of an algorithm that works with numbers, we might consider the following algorithm (which takes one parameter N, a non-negative integer):