# 1/11: Group A: Combinatorics 1: Permutations.

Group B: Modular arithmetic; Euclidean algorithm

Group A: This is the first of a series of meetings devoted to combinatorics. We will see how permutations and combinations arise naturally in a variety of problems.

Group B: We will review the basics of modular arithmetic and Euclidean algorithm in preparation for * Unique factorization in exotic number systems * presented by Jared Weinstein in a series of two future meetings.