Learning number theory with Gauß

This wikibook is based on Gauß' Disquisitiones Arithmeticae. It will cover all content of the book of Gauß', but it will be punctually extended for one of two reasons: a) The extension is part of a modern number theory education, or b) the extension connects Gauß' work to more recent additions to mathematics. The former aspect (and actually the latter too) is of importance since we want this wikibook to be usable as a textbook for number theory. Furthermore, we strive to include the largest possible number of proofs. On occasion, we will add 'nice' theorems for their aesthetic value.

1. Congruent numbers
2. Prime factorisation
3. Greatest common divisor, least common multiple
4. Continued fractions
5. Linear equations
6. Systems of linear equations
7. Euler's totient function