Lecture 9 - Linear Congruences and Modular Inverses

In this lecture we study the idea of division in the integers modulo n. This turns out to be rather subtle. However there are some elements called "units" or "invertible elements" that we're always allowed to divide by. These turn out to be the elements that are coprime to the modulus.

This lecture is part of a course in Number Theory (Math 301, University of Washington)