Another use for binary numerals
William Dunkum · The Arithmetic Teacher · 1970
One morning, while engaged in preparing problems in permutations and combinations, I found it necessary to list the subsets of the set S = {A, B, C, D, E}. As is well known, if there are n elements in a set S, then there are 2” subsets of the set, including the empty set Ø and the set S itself. However, tabulating all of the subsets is rather tedious and, even if done carefully, listing them often produces duplications or omissions which must be eliminated by cross-checking.