Step 1

A permutation of {a, b, c} is the listing of the three elements in the set in any order (without repeating any of the elements).

All possible permutations of {a, b, c} are the

abc, acb, bac, bca, cab, cba

Step 1

To enumerate all the permutations in ascending alphabetical order, list all the permutations beginning with A, then those beginning with B, C, D.

For each choice of initial letter, enumerate each of the possible permutations of the three remaining letters similarly, etc.

ABCD ABDC ACBD ACDB ABCD ADCB

BACD BADC BCAD BCDA BDAC BDCA

CABD CADB CBAD CBDA CDAB CDBA

DABC DACB DBAC DBCA DCAB DCBA