JCHL Sets

JCHL Sets

Sets are about sorting things into groups. Venn diagrams, unions and intersections — a friendly place to start the course.

Your progress through this topic0 of 8 lessons

Lessons in this topic

All 8 lessons, in order — each one ticks off as you open it.

Key ideas in this topic

Every formula from these lessons in one place. The green ones are printed in the log tables booklet you get in the exam — the red ones you learn off.

★ Must learn
Union (A ∪ B)
Union (A ∪ B)

Everything that is in A OR B (or both).

JCHL Sets 2

★ Must learn
Intersection (A ∩ B)
Intersection (A ∩ B)

Only the overlap — elements in BOTH A and B.

JCHL Sets 2

★ Must learn
Set difference (A \ B)
Set difference (A \ B)

The elements that are in A but NOT in B.

JCHL Sets 3

★ Must learn
Complement (A′)
Complement (A′)

Everything in the universal set that is NOT in A.

JCHL Sets 3

★ Must learn
Improper subsets

Every set has two improper subsets: the set itself, and the null (empty) set ∅.

JCHL Sets 4

★ Must learn
Number of subsets
Number of subsets

A set with n elements has 2ⁿ subsets in total (including itself and ∅).

JCHL Sets 4

★ Must learn
Cardinal number (#A)
Cardinal number (#A)

The NUMBER of elements in a set — the answer is just a number, not a set.

JCHL Sets 5

★ Must learn
Commutative property
Commutative property

Order does not matter for union and intersection.

JCHL Sets 6

★ Must learn
Associative property
Associative property

Where you put the brackets does not matter for union and intersection.

JCHL Sets 7