20.1 Integers | | Basic integer types and concepts |

20.2 Integer Division | | Integer division with guaranteed rounding. |

20.3 Floating Point Numbers | | Basic concepts. IEEE 754. |

20.4 Floating-Point Number Classification Functions | | The five kinds of floating-point number. |

20.5 Errors in Floating-Point Calculations | | When something goes wrong in a calculation. |

20.6 Rounding Modes | | Controlling how results are rounded. |

20.7 Floating-Point Control Functions | | Saving and restoring the FPU's state. |

20.8 Arithmetic Functions | | Fundamental operations provided by the library. |

20.9 Complex Numbers | | The types. Writing complex constants. |

20.10 Projections, Conjugates, and Decomposing of Complex Numbers | | Projection, conjugation, decomposition. |

20.11 Parsing of Numbers | | Converting strings to numbers. |

20.12 Old-fashioned System V number-to-string functions | | An archaic way to convert numbers to strings. |