Combinatorics

Companion notes for counting, arrangements, and related algebra topics.

All Algebra Factorials Permutations Combinations

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Combination Formula

June 25, 2026 · Algebra / combinatorics / combinations · Companion

A JoeCMath companion guide for the combination formula and why combinations divide by r factorial.

Jun 25, 2026 · Algebra / combinatorics / combinations · Companion

A JoeCMath companion guide for the combination formula and why combinations divide by r factorial.

Jun 24, 2026 · Algebra / combinatorics / permutations · Companion

A JoeCMath companion guide for introductory permutations, using a pizza competition example and a president/vice president example.

Jun 23, 2026 · Algebra / combinatorics / factorials · Companion

A JoeCMath companion guide for factorials and how they count the number of possible arrangements.