Discrete Math "Proper Subsets" Hey everyone, I am confused on part of this. Any input would be much appreciated!! X has ten members. How many members does ~P(X) have? (~P is the set of all subsets) How many proper subsets does X have? Well the number of members of ~P is 2^10 or 1024. This is the number of members in the set of subsets. What I'm confused about is how many proper subsets does X have?