Question 481365
Set A has six elements. To choose a subset, we can choose whether we want king to be in the subset or not; we can choose whether we want queen to be in the subset or not, and so on. This leaves 2*2*2*2*2*2 = 64.


Or we can go case-by-case where we choose zero-element subsets, one-element subsets, etc. in which the number of subsets is 6C0 + 6C1 + ... + 6C6, also equal to 64.