Math 0309

Integers

-3,-2,-1,0,1,2,3

whole numbers

0,1,2,3,4...

Natural numbers

1,2,3,...

rational number

A number that can be written as a fraction

⊆

A subset of or equal to. If every element of A is an element of B, then A is a subset of B.

real numbers

All numbers

U Union

Everything in group A and group B

logical connectives

Include and, or, not and if...then.

∀ Quantifiers

Indicate how many cases of a particular situation exists. All, Each, Every.

∈

It belongs to, member of, is an element of.

roster method

Listing each item in a set within braces

irrational numbers

Numbers that cannot be expressed as a ratio of two integers. Their decimal expansions are nonending and nonrepeating.

∃ Existential

Some, There exists, for at least one.

absolute value

The distance a number is from zero on a number line

∩ Intersection

The elements two or more sets have in common

statement

a sentence that is either true or false

` Prime

a whole number greater than 1 whose only factors are 1 and itself. A factor is a whole numbers that can be divided evenly into another number. The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.

Λ Conjunction

compound statement formed by joining two statements with the connector AND. The conjunction "p and q" is symbolized by p q. A conjunction is true when both of its combined parts are true; otherwise it is false.

∅

empty set; set with no elements

V disjunction

is false if and only if both statements are false; otherwise it is true.

x | x

such that

~ Negation

the opposite of the original statement