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Combinatorics
Counting methods for probability and statistics: permutations, combinations, factorials, and binomial coefficients for tallying outcomes systematically.
Binomial Theorem and Binomial Coefficient Explained
Learn the binomial theorem formula, how to expand binomial expressions, and how binomial coefficients and Pascal's triangle connect to give every term.
Combination Formula: Definition, Examples & Method
Learn the combination formula C(n,r) = n! / (r!(n-r)!), work through fully worked examples, and know when to use combinations instead of permutations.
Permutations vs. Combinations: What's the Difference?
Learn the key difference between permutations and combinations, when to use each, and how to apply their formulas with fully worked step-by-step examples.
Permutations: Formula & Examples
A permutation is an ordered arrangement of items. Learn the permutation formula, work through examples, and avoid the most common calculation mistakes.
The Fundamental Counting Principle Explained: With Examples
The fundamental counting principle lets you count all possible outcomes of a multi-step process by multiplying the number of choices at each step.