Question

How many proper subsets does S = {A, B, C, D} have?

Answer 1

Subsets are

(A,B,C)

(A,C,D)

(B,C,D)

(A,B) (A,C) (A,D) (B,C) (B,D) (CD)

(A). (B). (C). ( D)

There are 13 proper subsets

Answer is 13