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).