This document introduces the binomial probability distribution, which models experiments with a fixed number of trials (n), two possible outcomes per trial (success or failure), and a constant probability (p) of success on each trial. The binomial formula calculates the probability of getting exactly x successes in n trials. Several examples demonstrate calculating probabilities of outcomes like getting a certain number of successes or failures when rolling dice, patients recovering from a disease, making phone calls, hitting targets, and having boys in a family.