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23 Cards in this Set
 Front
 Back
Set

a collection of objects, which are called elements.


3 Methods Used to Indicate Sets

1) Description
2) Roster Form 3) SetBuilder Notation 

Description of Sets

use words
a simple sentence Ex: The set of blue items. The set of triangles 

Roster Form

listing all elements in the set
use braces { } Ex: {yellow triangle, blue triangle} 

SetBuilder Notation

uses symbols
Ex: D= {x I x is a triangle} 

Natural Numbers

{1, 2, 3, 4, ...}
symbol: N 

Whole Numbers

{0, 1, 2, ,3, ...}


Integers

{..., 2, 1, 0, 1, 2, ...}


Finite

has a stopping point
"countable" 

Infinite

never ending
fractions 

Equality of Sets

Sets A and B are equal if they contain exactly the same elements.
Ex: A= {1, 2, 3} B= {3, 1, 2} A=B 

Equivalent of Sets

Contain the same number of elements
Ex: A= {a, b, c} B= {d, e, f} 

Cardinality

How many elements are in the set
written as: n(A) Ex: A= {a, c, 1, 4, 5) n(A)=5 

Null or Empty Set

no elements in the set
written as { } or ∅ 

Universal Set

All elements in the context of the problem
written as U 

Subset

A is a subset of B if and only if all elements of A are contained in B


Proper Subset

A is a proper subset of B if and only if A is a subset of B AND A does not equal B.


{}

is a subset of every set and a proper subset


Number of Subsets

2 , where n is the number of elements in the set


Complement

A all elements not in A


Union

A B
or 

Intersection

A B
and 

Number of Proper subsets

2 1
