In competitive programming, probability problems typically involve calculating the likelihood of an event happening. The basic principle is to divide the number of favorable outcomes by the total number of possible outcomes. Problems may involve dice rolls, card draws, or random selections, where you’ll need to use combinatorics or simulations to count outcomes. Additionally, concepts like conditional probability, expected value, and independence may come into play. Mastering these concepts helps in tackling probability-related problems with confidence, especially when combined with techniques like dynamic programming or memoization.