How Many Subsets?

Consider the set S

1) How many total subsets does S have? A subset of S is a set A whose elements are all elements of S.

2) How many subsets of S contain the element 4?

3) How many subsets of S are of size 4?

4) How many subsets of S contain only odd numbers?

As usual, try to come up with a few different ways to approach these problems. What are some other interesting questions we could ask?