Permutations and combinations

Permutations and ArrangementsSign up

understand the term permutation and apply the counting (multiplication) principle · arrangements of n distinct objects in a line (n!) and r from n (nPr = n!/(n-r)!) · arrangements involving repetition (e.g. arranging the letters of NEEDLESS) · arrangements involving restriction (e.g. people in a line where two must, or must not, be adjacent), including two or more rows

Combinations and SelectionsSign up

understand permutation vs combination (order matters vs not) · use nCr = n!/(r!(n-r)!) to count selections of r from n · solve selection problems including selections subject to conditions/restrictions (9709 excludes circular arrangements)