Stage 32 · Counting, Permutations, Combinations & the Binomial Theorem

32.2.5 Permutations with Restrictions (II): Together and Apart

32.2 Permutations: When Order Counts Too

Point 5 of 6

32.2.5 Permutations with Restrictions (II): Together and Apart

Core idea

If two must be side by side, 'bundle' them into one block; if they mustn't touch, arrange the others first and then 'slot' them into the gaps

Module goal. Understand counting where the selection is ordered, master the permutation formula and factorials, and learn to spot permutation problems that carry restrictions

eastmath.com · 32.2 Permutations: When Order Counts Too · 32.2.5 Permutations with Restrictions (II): Together and Apart