Computers move numbers around. That's all they do. Everything they do - playing music, drawing, going on the Internet - is done by moving numbers around. It's important for us as computing professionals to understand how this is done.
For example, how do we count? You probably haven't thought about it since you were five. It's important, however, to think about how we count 'normally' before we attempt to figure out how computers do it.
Look down. Chances are that you have ten digits, and that provides a clue about how counting works.