1. It is the whole universe under consideration.
show them how to shade in the same direction for unions and different directions for intersection.
The universal set is U.
It is the whole universe under consideration.

2. Everything outside set A is its complement A’.
show them how to shade in the same direction for unions and different directions for intersection.
Everything outside set A is its complement A’.

3. A B
show them how to shade in the same direction for unions and different directions for intersection.
A B U

4. A B
A B U

5. A B
Teach them to use two different colors or two different stroke directions and then to watch where they show up.
A B U

6. A B
A B U

7. B A C
A B C’ U U

8. B A C
A B C’ U U

9. B A C
(A C) B U U

10. B A C
(A C) B U U