1980 Allston Way

Berkeley, CA 94704

USA

**Facilitator**: Bruce Cohen — After over 25 years of teaching high school math (primarily geometry and calculus using a student centered, group work approach), I “graduated” from Lowell High School in June 2018. Last Fall at SFSU and this Spring at USF, I have been co-teaching number theory, focusing on setting inquiry-based learning tasks. I’ve been involved with both student and teacher math circles for many years, and currently serve on the leadership team of the SFMTC. Graduation has also allowed me to spend more time with my three young granddaughters.

**Topic**: Exploring Arithmetic Functions — An arithmetic function is a function where the domain (input set) is the positive integers. An example would be d(n), a function that returns the number of (positive) divisors of n. So d(12)=6 because 1,2,3,4,6, and 12 are the divisors of 12. We’ll begin with an exploration of some modular arithmetic (e.g. clock arithmetic, 10+4=2 on a 12 hour clock) that will motivate the definition of a very useful arithmetic function. We’ll look for ways to efficiently compute the value our function without actually counting.

If you plan to attend, **RSVP** [here – Link soon!].