ABSTRACT
In this chapter, we introduce the most basic idea of number theory, divisibility. This in turn leads naturally to a discussion of primes, the “building blocks” of the positive integers. As discussed in Chapter 0, the prime numbers have fascinated people for centuries, and even today their patterns and distribution remain objects of intense scrutiny. Before getting to these topics, however, we need to introduce two principles of number theory that will be used repeatedly throughout this book.
