Fixed-point numbers implement floating-point operations using ordinary integers. This is accomplished through clever scaling, allowing systems without explicit floating-point hardware to work with floating-point values effectively. In this chapter, we explore how to define and store fixed-point numbers; how to perform signed arithmetic with fixed-point numbers; how to implement common trigonometric and transcendental functions using fixed-point numbers; and, lastly, discuss when one might wish to use fixed-point numbers in place of floating-point numbers, including an example of an emerging use case involving modern neural networks.