An introductory discussion of unions, intersections, and complements in the context of basic probability. I include a discussion of mutually exclusive events, as well as the addition rule. I work through a simple die rolling example, and also an example of a scenario where we randomly sample from a population of people, where some have diabetes and some have hypertension. The various scenarios are illustrated with Venn and Euler diagrams. (The percentages given in the video are loosely based on statistics for 50 year-old Canadian males.)