The "If/Then" statement is a logical construct used to express a condition and its outcome. It follows the format "If condition, then result." For example, "If it rains, then the ground will be wet." This structure helps in making predictions based on specific scenarios. In programming and mathematics, "If/Then" statements are essential for decision-making processes. They allow computers to execute certain actions based on given conditions. For instance, in a game, "If the player scores, then increase the score counter." This helps create interactive and responsive systems.