Download Section 1.4

The Real Number System


Natural Numbers (AKA Counting Numbers):
{1, 2, 3, 4, …}
Whole Numbers (Natural Numbers plus zero):
{0, 1, 2, 3, …}
NOTE: Both of these sets include only positive
numbers!


Integers (We now include negative whole
numbers): { …-3, -2, -1, 0, 1, 2, 3, …}
Rational Numbers (any number that can be
written as a fraction).
This includes all whole numbers, all fractions,
and decimals that either terminate or have a
repeating pattern.


Irrational Numbers: Numbers that cannot be
written as a fraction. These are certain types
of square roots (√2) and numbers like π.
Both of these are decimals that never end and
never repeat.
Empty set: { } Means there are no values in
the set.
Real Numbers
Rational
Numbers
Non-integers
Integers
Negative
Integers
Irrational
Numbers
Whole
Numbers
Zero
Natural
Numbers






1) ¾ is an integer.
2) √3 is a real number.
3) 9.2 is a rational number.
4) Every counting number is a rational
number.
5) -2 ½ is a rational number.
6) 0 is not a positive number.