the.com/combinatorics
The math of counting things without actually counting them, one at a time, like a fool.
means The branch of mathematics concerned with counting, arranging, and selecting objects from a set — figuring out how many ways something can be done.
from From 'combination,' tracing back to Latin 'combinare' (to combine) — 'com-' (together) plus 'bini' (two by two). The '-torics' ending is a mathematical dressing-up, echoing words like 'calculus' and 'mechanics' to signal a formal field of study. The term 'combinatorics' itself is a relatively modern label — the underlying ideas are ancient (people were counting arrangements of things long before the word existed), but the field only got its tidy name as mathematicians in recent centuries organized it into a discipline of its own.
- birthday paradox
- 23 people give 50% shared-birthday odds
- chess positions
- more possible games than atoms in universe
- core trick
- turns impossible tallies into clean formulas
- deceptively simple
- hardest problems look like kids riddles