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

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

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

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?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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?