"Less Than" using sets:
If A and B are finite sets then n(A) is less than n(B), written n(A)<n(B), if A is equicalent to a proper subset of B. So if n(A)=a & n(B)=b, then a<b. Similarly we define greater than: n(A)>n(B) or a>b, which is n(B)<n(A) or b<a, respectively.