Unions, intersections and overlapping events

Practice unions, intersections, and overlapping events using words, numerical models, a Venn diagram, and a two-way table. This precalculus probability set emphasizes inclusive “or,” the role of an intersection, and careful counting of exactly one event or neither event. Single-select and multiselect problems develop from basic event notation to checking whether proposed probabilities are consistent. Detailed explanations show why overlap must be subtracted and why mutually exclusive events should not automatically be treated as independent.