Stage 32 · Counting, Permutations, Combinations & the Binomial Theorem
32.1.2 The Addition Principle (Counting by Cases)
32.1 The Two Counting Principles: Where All Counting Begins
Point 2 of 6
32.1.2 The Addition Principle (Counting by Cases)
Core ideaTo travel out of town you can take a train or a bus — the choices don't overlap and each is counted on its own, so the total is just the cases added up, N = m1 + m2 + ...
Module goal. Build the two basic habits of mind — add when you sort into kinds, multiply when you go step by step — and learn to tell whether a task is a 'sort' or a 'sequence', laying the foundation for permutations and combinations