> For the complete documentation index, see [llms.txt](https://cryptohack.gitbook.io/cryptobook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cryptohack.gitbook.io/cryptobook/fundamentals.md).

# Fundamentals

- [Mathematical Notation](https://cryptohack.gitbook.io/cryptobook/fundamentals/notation.md)
- [Division and Greatest common divisor](https://cryptohack.gitbook.io/cryptobook/fundamentals/division-and-gcd.md): Author: Zademn
- [Euclidean Algorithm](https://cryptohack.gitbook.io/cryptobook/fundamentals/division-and-gcd/euclidean-algorithm.md)
- [Modular Arithmetic](https://cryptohack.gitbook.io/cryptobook/fundamentals/modular-arithmetic.md): Authors: A~Z, perhaps someone else but not yet (or they've decided to remain hidden like a ninja)
- [Theorems of Wilson, Euler, and Fermat](https://cryptohack.gitbook.io/cryptobook/fundamentals/modular-arithmetic/theorems-of-wilson-euler-and-fermat.md)
- [Fermat's Little Theorem in Detail](https://cryptohack.gitbook.io/cryptobook/fundamentals/modular-arithmetic/theorems-of-wilson-euler-and-fermat/fermat-euler-theorem.md): Would you like to be an author?
- [Euler's Theorem in Detail](https://cryptohack.gitbook.io/cryptobook/fundamentals/modular-arithmetic/theorems-of-wilson-euler-and-fermat/eulers-theorem-in-detail.md)
- [Quadratic Residues](https://cryptohack.gitbook.io/cryptobook/fundamentals/modular-arithmetic/quadratic-residues.md)
- [Continued Fractions](https://cryptohack.gitbook.io/cryptobook/fundamentals/continued-fractions.md)