The document defines some basic concepts about sets using a standard deck of playing cards as an example. It introduces the full deck of cards as the set D, then defines subsets A (aces) and C (face cards). It explains that the union of sets A and C, written A ∪ C, contains all the elements that are in either A or C (all the aces and face cards).

1. introduction

2. sets

4. 









5. A Set – The cards in a standard deck
D = {A♥, A♦, A♠, A♣, 2♥, 2♦, 2♠, 2♣, ··· J♥, J♦, J♠, J♣, Q♥, Q♦, Q♠, Q♣, K♥, K♦, K♠, K♣}

6. Note: The order of the elements doesn’t
matter; D can be written:
D = {2♥, 2♦, 2♠, 2♣, ··· J♥, J♦, J♠, J♣, Q♥, Q♦,
Q♠, Q♣, K♥, K♦, K♠, K♣, A♥, A♦, A♠, A♣}

7. subsets

8. A = Set of Aces: A is a subset of D
A  B

9. C = Set of Face Cards: C  D

10. operations

11. Union of 2 sets: the set of elements in both
sets; A  C = all the aces and face cards:
A  C = {A♥, A♦, A♠, A♣, J♥, J♦, J♠, J♣, Q♥, Q♦, Q♠, Q♣, K♥, K♦, K♠,
K♣}