The following is a listing of real numbers:
| Natural | 1, 2, 3, 4, … |
| Whole | 0, 1, 2, 3, 4, … |
| Integers | … -4, -3, -2, -1, 0, 1, 2, 3, 4, … |
| Rational | Any number that can be written in the form of p/q, where p and q are integers and q ≠ 0. |
| Irrational | Any real number that is not rational. |
- Every natural number is a whole number.
- Every whole number is an integer.
- Every integer is a rational number.
- All real numbers can be written in decimal form.
- Rational numbers in decimal form are either terminating or repeat forever.
- Irrational numbers are decimals that never terminate or repeat.
- Integers are rational numbers because they can be written in the form:
| Terminating Example | .15, .128 |
| Repeating Example | 1.33, 4.7234 |
Irrational numbers are decimals that never terminate or repeat. An example would be π (pi).