Answer:
20. A' { 8, 9, 10 }
21. B' { 1, 2, 3, 4, 5, }
22. AUB { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
23. A∩B { 6, 7 }
24. A-B { 1, 2, 3, 4, 5 }
25. B-A { 8, 9, 10 }
Explanation:
We use (') (the apostrophe) to denote the complement of a set.
A' is all the items which are not in set A. While B' is all the items which are not in set B
AUB, or read as "The union of A and B" is the set of all elements that belong to either A or B or both.
A∩B or read as “A intersection B” or “the intersection of A and B”—is defined as the set composed of all elements that belong to both A and B.
A-B is the set of all elements that are in A but NOT in B, and B-A is the set of all elements that are in B but NOT in A.
