
Absolute Value
(Positive) distance between a number and zero on the number line; the corresponding "unsigned" number.   4 = 4 and  4 = 4.

Counting Numbers
Also called natural numbers, the set of positive numbers used to count objects. 1, 2, 3, 4, 5, ...

Integers
The set of numbers including all the whole numbers and their opposites (the positive whole numbers, the negative whole numbers, and zero)  fractions and decimals are not integers. ... 3, 2, 1, 0, 1, 2, 3, ...

Irrational Numbers
The set including all numbers that are non terminating, non repeating decimals.

Natural Numbers
The set of positive numbers used to count objects (also called counting numbers). 1, 2, 3, 4, 5, ...

Negative Numbers
The set of numbers to the left of zero on the number linenumbers less than zero.

Number Line
A horizontal line that has points that correspond to numbers. The points are spaced according to the value of the number they correspond to; in a number line containing only whole numbers or integers, the points are equally spaced.

Opposite
A number that is the same distance from zero as a given number, but on the opposite side of zero. For example, 7 and 7 are opposites, and 9 and 9 are opposites.

Positive Numbers
The set of numbers to the right of zero on the number linenumbers greater than zero.

Rational Numbers
The set of numbers including all the integers, plus all the fractions, or terminating decimals and repeating decimals. Every rational number can be written as a fraction a/b, where a and b are integers.

Real Numbers
The set of all the rational numbers and all the irrational numbers.

Whole Numbers
The set of numbers including all the natural numbers and zeronegative numbers are not whole numbers. 0, 1, 2, 3, 4, ...