Natural numbers
1, 2, 3... (when you ask a child to start counting)
Whole number
Natural numbers + 0
Integers
Whole numbers including those that are negative -3, -2, -1, 0, 1, 2, 3
Rational numbers
fractions, decimals (terminating or repeating), including integers, whole numbers, etc.
Irrational numbers
any decimal that goes on forever pi, square root of 2
set
any collection of objects, people, or things that are carefully defined
member or element
what a term inside a set is called
E
used to say "is an element of" 7 E {prime numbers}
O w/ line through it
empty set, can also be written as { }
subset
A = {0, 1, 2, 3} subsets: {0} {1} {2} {3} {o} {0, 1, 2, 3}
intersection
a ________ of two sets consists of the elements they have in common symbol is like: n A n B = C or {2,4,6,8,10} n {3,4,5,6,7,8} = {4,6,8}
union
when ALL the elements of both sets are listed without repeating any elements twice sign is u