Counting Methods, Permutations and Combinations (Edexcel A-Level Further Mathematics): Quizzes

$120$

$60$

Add different cases; multiply within

When order matters

When order doesn't matter

$\frac{n!}{(n-r)!}$

$\frac{n!}{r!(n-r)!}$

$60$

$167,960$

$72$