# Module 2: Number Theory and Relations

## Divisibility and Modular Arithmetic

Video: Divisibility

Video: Modular Arithmetic

## Integer Representations

## Primes and Greatest Common Divisors

Video: Prime Numbers

Video: The GCD and Euclid’s Algorithm

## Relations and Properties

Video: Properties of Relations

## Representing Relations

Video: Representing Relations

## Equivalence Relations

Video: Equivalence Relations