Set Notation & Venn Diagrams Flashcards

All 6 cards in this deck

What does $A \cap B$ mean?

The intersection: the elements that are in both $A$ and $B$ (the overlap).

What does $A \cup B$ mean?

The union: the elements that are in $A$ or $B$ or both.

What does $A'$ mean?

The complement of $A$: everything in the universal set that is not in $A$.

In set notation, what does $\xi$ (also written $E$) stand for?

The universal set: all the elements being considered, shown by the rectangle round the Venn diagram.

What are the steps to complete a Venn diagram from two lists?

e.g. $\xi=\{1,...,10\}$, $A=\{$multiples of $3\}$, $B=\{$even numbers$\}$

1. Put the elements in both sets in the intersection: $6$
2. Fill each 'only' region: $A$ only $3, 9$; $B$ only $2, 4, 8, 10$
3. Put the elements left over outside both circles: $1, 5, 7$

True or false? If 20 students study French and 8 study both French and German, you write 20 in the 'French only' region.

False. Write $20-8=12$, because the 20 already includes the 8 in the intersection.