You know my methods. Apply them.
Sherlock Holmes in Arthur Conan Doyle, The Hound of the Baskervilles
The set of integer numbers is among the simplest objects in mathematics. These numbers have a whole theory devoted to them, called, not surprisingly, number theory. In this chapter we will consider a small part of this theory. The aim is to provide you with mathematics that you will often need but, more importantly, we will apply the earlier methods to see how they illuminate the material.
What basic properties ...