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Symbols for writing sets


anytime numbers are enclosed in parentheses or brackets and separated by commas they are said to be part of a set

example {-2, 0, , .75}


We often use Venn diagrams to show how sets combine and intersect.

for example look at the values in the following sets:

set A {0, 1, 2, 3, 4}

set B { -2, -1, 0, 1}

Venn Diagram of Sets A & B







The union of two sets are all the items that are in both of the sets. We use the symbol          to symbolize union.  It means the combination of two sets.

 For example: A          B  = {-2, -1, 0, 1, 2, 3, 4}


The intersection of two sets are only the items that are common to both sets.  we use the symbol ∩ to symbolize intersection.   The intersection of A and B is symbolized by A∩B

For example: A∩B  = { 0,1}