# BATMATH

**Bay Area Teachers and Mathematicians**

## Math Teachers’ Circles

## AIM Math Teachers’ Circle – San Jose

## Monterey County Math Teachers’ Circle

## San Francisco Math Teachers’ Circle

## Wine Country Math Teachers’ Circle

## AIM Math Teachers’ Circle – Stanford

## Morgan Hill Math Teachers’ Circle

## San Joaquin Math Teachers’ Circle

## East Bay Math Teachers’ Circle

## San Benito County Math Talks

## Santa Cruz Math Teachers’ Circle

### San Benito County Office of Education

460 5th St, Hollister, CA 95023

### Sonoma County Office of Education

5340 Skylane Blvd, Santa Rosa, CA 95403

### Sonoma State University

1801 E Cotati Ave, Rohnert Park, CA 94928

### MBAMP - Math Department UC Santa Cruz

1156 High St, Santa Cruz, CA 95064

### San Joaquin County Office of Education

2922 Transworld Dr, Stockton, CA 95206

### Proof School

555 Post St, San Francisco, CA 94102

### Barrett Elementary Schoool

895 Barrett Ave, Morgan Hill, CA 95037

### Stanley Middle School library

3455 School St, Lafayette, CA 94549

### CSU East Bay

25800 Carlos Bee Blvd, Hayward, CA 94542

### American Institute of Mathematics

600 E Brokaw Rd, San Jose, CA 95112

### Nora Suppes Hall 103

224 Panama St, Stanford, CA 94305

### CSU Monterey Bay

**Facilitator**: **Marc Roth** — Currently a math teacher at Main Street Scholars in Half Moon Bay, veteran MTC and conference speaker, and retired after 43 years as a public school secondary math teacher. BA in mathematics from UC Berkeley.

**Topic**: **Niceties of the Harmonic Mean** — The harmonic mean is a very interesting but largely neglected topic. It can enrich the pre-algebra, algebra, and geometry curriculum. We will first discover a little-known method of how to locate the harmonic mean of two numbers on the number line by looking at it as a special weighted average. This will lead to valuable worksheets that provide multi-step fraction practice but can also lead students to discover an interesting pattern. We will then extend the analysis and introduce further worksheets. If time permits, we will also look at the connection to Pythagorean triangles, which are right triangles, each of which has three sides of integer length. The best example is the 3-4-5 right triangle. This topic will be supported with original geometry tiles.

If you plan to attend, **RSVP** here.

**Session leader**: Sam Vandervelde

**Session title**: Full Brain Workout

**ABSTRACT**: The first portion of our afternoon session will feature `prickly primes’ and immerse us in the world of algebra and number theory. Following in the footsteps of Euler, our primary goal will be to prove the existence of infinitely many of these sorts of primes, although we will encounter several other nice results from elementary number theory along the way. After this triumph, we will take a short break and then turn to the quite different field of knot theory, in which we will seek to adapt the invariant polynomial provided by the Kauffman bracket in the hopes of producing an elementary knot invariant that can distinguish left and right handed trefoil knots.

**BIO**: Sam Vandervelde is the Head of School and Dean of Mathematics at Proof School, a full curriculum day school in San Francisco serving students who love math from throughout the Bay Area. He was previously the chair of the math department at St.Lawrence University, where he taught for eight years. Prior to this stint he spent several years situated near Stanford; during this time he launched the Stanford Math Circle, helped to create the organization that runs Math Teacher Circles, and wrote Circle in a Box, a handbook for math circle leaders.

Please RSVP at this link. Thanks! We look forward to seeing you there.

Presenter: Matt Beck (San Francisco State University)

Facilitator: **Henri Picciotto ****http://www.mathedpage.org/**

Topic: **The geoboard** is a great learning environment, but in this session we will use it as an arena for puzzles and problems, some of them unsolved. Those involve triangles, non-triangles, and zigzags.

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

**This month’s Topic: **How many squares are in a grid?

**Description**: We begin with the simple task of counting the number of squares in a small grid. Then we do as all mathematicians to and will try to generalize to bigger grids, while also exploring related geometric ideas and making connections to other areas of mathematics.

**About this month’s speaker, ****Sean Gasiorek:** I am a graduate student in the mathematics department at UC Santa Cruz in my sixth and final year(!) working with Richard Montgomery. I’ve been attending and presenting with the MTC since the 2015-16 academic year. I discovered my love of math in high school thanks to my passionate, motivating teachers, and enjoy giving back to the MBAMP community.

**Food: **Refreshments and snacks

- Experience the excitement of learning mathematics with a supportive group.
- Gain knowledge and confidence.
- Rediscover the thrill of learning mathematics for its own sake.

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**Henri Picciotto**