Integers are perhaps the most important class of numbers. This is certainly true in the case of computers. In this chapter, we dive into the integers and how computers represent and operate on them. Without these operations, digital computers would not function. We begin with some preliminary notation and terminology. Next, we take a detailed look at the unsigned integers. We follow this with an examination of negative integers and their operations. Lastly, we finish with a look at binary-coded decimals.