Question

Let A = {2, 3, 5, 7, 11, 13} and B = {A, 2, 11, 18}.

1. Find A ∪ B. 2. Find A ∩ B. 3. Find A − B.

Answer 1

1) $A\cup B=\{2,3,5,7,11,13,A,18\}.$

2) $A\cap B=\{2,11\}.$

3) $A-B=\{3,5,7,13\}.$