#### Karl-Dieter Crisman

Digital versions | PDF and HTML |

PreTeXt source | Yes |

Exercises | Yes |

Solutions | No |

License | Creative Commons-Attribution-No Derivatives 4.0 International License |

- Text for a first course in number theory
- Current edition date is July 2021
- 510 pages, 25 chapters
- More than 400 exercises
- Course adoption list
- For more information and to access PDF or online version

This is a textbook for a first course in number theory. In addition to the standard topics such as modular arithmetic, congruences, prime numbers, and quadratic reciprocity, there is emphasis on the geometric aspects, substantial material on cryptography, and an introduction to analytic number theory. Almost all the concepts are illuminated with snippets of Sage code that is well-integrated into the presentation. In the online HTML version the Sage code can be run and modified by students as they read the text. The text has been class tested at Gordon College over several iterations and it has been adopted at two dozen institutions.