1. Let S = {1, 3, 5, 7} and T = {2, 5, 7}. Give an example of a subset of T that is not a subset of S.
2. Suppose that S and T are subsets of the set U. Under what circumstance will S ∩ T = T?
3. Suppose that S and T are subsets of the set U. Under what circumstance will S ∪ T = T?
4. Find three subsets of the set of integers from 1 through 10, R, S, and T, such that R ∪ (S ∩ T) is different from (R ∪ S) ∩ T.