Theory of Numbers: Fermat's Theorem and Modular Arithmetic

This lecture is part of an online undergraduate course on the theory of numbers.

We prove Fermat's theorem a^p = a mod p. We then define the order of a number mod p and use Fermat's theorem to show the order of a divides p-1. We apply this to testing some Fermat and Mersenne numbers to see if they are primes.




For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj52Qf7lc3HHvHRdIysxEcj1H