SETS - symbols in maths

#

CARDINAL NUMBER of a set COUNT the number of elements in a set. Set A = {1, 2, 3} There are 3 elements in Set A #A = 3

A'

COMPLEMENT of a set A everything EXCEPT A The set of all elements in the universal set that are not in a given set.

∩

INTERSECTION is the set of all elements that both sets have in common. Set A = {1, 2, 3} and Set B = {3, 4, 5} 3 is in both Set A and Set B A∩B is 3

{ }

NULL SET or EMPTY SET Set C is the number of girls attending St Mary's CBS. Set C = { }

∅

NULL SET or EMPTY SET Set C is the number of girls attending St Mary's CBS. Set C = ∅

Venn Diagram

A diagram that uses circles to display elements of different sets. Overlapping circles show common elements.

A/B

SET DIFFERENCE (read as A not B) All elements of set A that does NOT exist in the set B. Exclude B

U

UNIVERSAL It is the largest set you are using when working with sets. E.g. If looking at student's favourite sports at your school. The UNIVERSAL set is EVERY student in the school.

∉

is NOT an element of Set A = {1, 2, 3} 6 ∉ A

⊂

is a SUBSET a set whose elements all belong to another set. Set A = {1, 2, 3} and Set D = {2, 3} D ⊂ A

∈

is an ELEMENT of a set. is a MEMBER of a set. Set A = {1, 2, 3} 1 ∈ A

∪

UNION the set of all elements that belong to two sets with NO repeats. Set A = {1, 2, 3} and Set B = {3, 4, 5} A∪B = {1, 2, 3, 4, 5}