Subsets:

1). How many subsets of the integer set {1,2,3,...10} are there?

2). How many subsets of the integer set {1,2,3,...10} are there that has size = 5?

3). How many subsets of the integer set {1,2,3,...10} contain precisely one multiple of 3 and no other elements within 1 of that multiple of 3?