Lisamispõhimõte

The lisamispõhimõte, which translates to "addition principle" or "addition rule" in English, is a fundamental concept in mathematics, particularly in combinatorics and probability theory. It describes how to count the total number of possible outcomes when there are multiple, mutually exclusive options.

The principle states that if there are *n* ways to do one thing and *m* ways to do another, and these two actions cannot be done at the same time, then there are *n + m* ways to do either one action or the other. The key condition is that the sets of outcomes for each action must be disjoint; there should be no overlap between the possibilities.

For example, if a student can choose to take either a math course or a physics course, and there are 5 different math courses and 3 different physics courses available, and no course is both math and physics, then the student has 5 + 3 = 8 choices in total. This principle is foundational for understanding more complex counting problems and forms the basis for calculating probabilities where events are mutually exclusive. Its simplicity belies its importance in building more intricate mathematical structures.