Topic explanation

Standard explanation

'Arrange', 'line up', 'first, second, third', 'codes', 'passwords order' -> permutation. President, VP, secretary from 10 people: 10P3.

Key points

• order words
• order matters
• nPr = n! / (n-r)!
• r <= n
• RECOGNIZING PERMUTATION PROBLEMS: 'Arrange', 'line up', 'first, second, third', 'codes', 'passwords order' -> permutation. President,
• WORDING: 'Arrange', 'line up', 'first, second, third', 'codes', 'passwords order' -> permutation.
• WHAT — RECOGNIZING PERMUTATION PROBLEMS: 'Arrange', 'line up', 'first, second, third', 'codes', 'passwords order' -> permutation. President,
• WHY — Why it matters: This rule is a separate learning unit inside permutations npr. It can be defined, applied, and check

Labelled diagram