1. Sets and Venn Diagrams
We use the idea of sets to classify numbers and objects.
We use Venn diagrams to illustrate these sets.

2. Sets and Venn Diagrams Example
The sets A and B consist of the numbers 0, 1, 2, 3, …, 9 so that
Set A = {4, 7, 9}
Set B = {1, 2, 3, 4, 5}
Illustrate these sets in a Venn diagram

3. Fill in the Venn diagram on your whiteboards
Sets and Venn Diagrams
Example
The sets A and B consist of the numbers 0, 1, 2, 3, …, 9 so that
Set A = {4, 7, 9}
Set B = {1, 2, 3, 4, 5} A B
Fill in the Venn diagram on your whiteboards

4. Did you have any mistakes?
Sets and Venn Diagrams
Compare your whiteboard to the solution
Many students will miss out the 0, 6 and 8
Did you have any mistakes?

5. Sets and Venn Diagrams Key vocabulary: intersection
The intersection of A and B = {4}
Think of the word AND.
Many students will miss out the 0, 6 and 8

6. Sets and Venn Diagrams Key vocabulary: union
The union of A and B = {1,2,3,4,5,7,9}
Think of the word OR.
Many students will miss out the 0, 6 and 8

7. Sets and Venn Diagrams Key vocabulary: complement
The complement of A ={0,1,2,3,5,6,9}
What do you think complement means?
Many students will miss out the 0, 6 and 8

8. Sets and Venn Diagrams Key vocabulary: complement
Think of the word NOT.
The complement of A = {0,1,2,3,5,6,9}
What is the complement of B?
Many students will miss out the 0, 6 and 8

9. On your whiteboards
any students will miss out the 0, 6 and 8

10. On your whiteboards
any students will miss out the 0, 6 and 8

11. On your whiteboards
any students will miss out the 0, 6 and 8

12. On your whiteboards
any students will miss out the 0, 6 and 8

13. In your books Answer the questions on worksheet 1 in your books.
any students will miss out the 0, 6 and 8

14. Set Notation We use the idea of sets to classify numbers and objects.
We use Venn diagrams to illustrate these sets.

15. Sets and Venn Diagrams Key vocabulary: intersection
Notation: This can be written as 𝐴∩𝐵
Many students will miss out the 0, 6 and 8

16. Sets and Venn Diagrams Key vocabulary: union
Notation: This can be written as 𝐴∪𝐵
Many students will miss out the 0, 6 and 8

17. Sets and Venn Diagrams Key vocabulary: complement of A
(everything not in A)
Notation: This can be written as 𝐴 ′
Many students will miss out the 0, 6 and 8

18. Sets and Venn Diagrams Other notation:
We use ξ (small Greek letter xi) to represent the universal set, that is the set from which we are choosing numbers or objects.
𝐴⊂𝐵 means that A is a subset of B. In other words every element of A is contained in the set B.
∅ is the empty set. In other words, a set with no numbers (or objects).
Many students will miss out the 0, 6 and 8

19. On your whiteboards
Many students will miss out the 0, 6 and 8

20. In your books
any students will miss out the 0, 6 and 8

21. Extra question
Think of the words AND, OR and NOT to try to figure out the more complicated questions.
Challenge question – can the students figure out what the notation means?