Illustrative Example 3. Use the diagram below to answer the questions that follow. 1. What elements are found in the union of A and B? 2. What is the cardinality of the union of A and B? 3. What elements are found in the inter- section of A and B? 4. What is the cardinality of the inter- section of A and B? 5. What are the elements in A'? of B'? Answers: U 11 A 4 14 20 B 5 7 23 21