Set notation
As it is common for set and probability questions to be asked in the section of tests and exams
where you are not allowed notes, it is important that you learn what all the symbols mean.
Match the symbols on the left with their meaning on the right. Some symbols have more than one
meaning shown, and some meanings have more than one symbol.
|A|
A is a subset of B
{… }
A is not a subset of B
A∩B
All of the elements in either set A or B or both
A∪B
All the members of set A are also members of set B
A⊂B
Only the elements that are in both set A and set B
A⊄B
Set B has elements that are not members of set A
A⊃B
Set B is a subset of Set A
A⊅B
Set B is not a subset of Set A
…∈A
The complement of set Set A
…∉A
The empty set
𝑛(A)
The intersection of A and B
𝑃(A)
... is a member of set A
𝕌
... is not an element of set A
∅
The number of members of set A
̅
A
The probability of A given B
{}
The probability that a random selection is a member of set A
A′
The set of ...
𝑃(A|B)
The union of A and B
The universal set