Applied Mathematics · Ch 6 — Permutations and Combinations
Fundamental Principles of Counting
6.3
Fundamental Principles of Counting
Counting is easy when you just list things out, but the moment the numbers get large, you need a smarter way. The fundamental principles of counting give you two simple rules — the multiplication principle and the addition principle — that let you count possibilities without writing every single one down. These aren't just formulas; they are the logical backbone for everything that follows in permutations and combinations. Once you see why the …
Figure 6.1A tree diagram for the fundamental principle of counting: 3 shirts each pairing with 2 trousers gives 3 times 2 equals 6 outfits
Drawn by us to help you understand the concept clearly, and verified to make sure it's accurate. For exams, practice from your NCERT textbook's own diagram.
The fundamental principle of counting as a tree: 3 × 2 = …