An Inside-Out Course on Number Theory (Pt 1)

This semester, I’m teaching a course entitled “Introduction to Number Theory” through the Inside-Out Prison Exchange Program. In short, what that means is that every Friday, I take a group of students from the Claremont Colleges (the “outside students”) with me to the California Rehabilitation Center to join 15 incarcerated students (the “inside” students) in learning some introductory topics in number theory.

The California Rehabilitation Center (CRC) is a medium-security state prison for men, located in Norco, California. Here’s a painting of CRC by Sandow Birk (held by the Pomona College Museum of Art).

“For [this] project I visited every one of California’s 33 state prisons and painted a picture of them. The idea was about the changes that California has gone through over its 150 years–from being seen in the 1850’s as an American Eden, where you could go west and dig out gold out of the ground and eat the oranges from the trees and it was always sunny and warm and you could strike it rich, to becoming the most incarcerated population on Earth. It’s shocking. And the more you learn about prisons the more nasty it all becomes.” — Sandow Birk

For over 20 years, the Inside-Out Prison Exchange Program, based at Temple University, has brought campus-based college students with incarcerated students for semester-long courses held in a prison, jail or other correctional setting all around the world. What I appreciate most about the organization is the way it approaches education as a collaborative endeavor and not one in which higher education professors and students go to a carceral organization to “help inmates” out of a sense of volunteerism or charity. Our local Inside Out program was started by Pitzer College and is run in part by a group of incarcerated men at CRC who make up our “Think Tank”. The truth is that I and the Claremont Colleges outside students are learning just as much as inside students are, if not more.

How are students selected? All students (inside and outside) are asked to fill out a questionnaire to find out why students want to take this course and what they hope to gain from the experience. There are several Inside Out courses that the Claremont Colleges offer each semester, and all of us instructors figure out how to allow the greatest number of students as possible to take our courses.

What are the goals of this course? While I do want students in this course to learn some interesting mathematics, the underlying goal of this course is for students to learn something about themselves and others through doing mathematics with each other. In particular, I am hoping that students in this class will have a more nuanced and complete understanding of what it means to be mathematically brilliant so that they can recognize that in themselves and others. This is one of the ways that I am hoping to create a rehumanizing mathematical experience for me and my students.

What is the course like? The Inside-Out Program is very particular about the kind of pedagogy we are to use. Lecture-based courses don’t provide for the kind of mutual engagement and co-learning that the program is trying to encourage. Therefore, I’ve structured my course using materials based off of my work with Bowen Kerins, Al Cuoco, Glenn Stevens in 2009 at the IAS/Park City Mathematics Institute Teacher Leadership Program.

On the first day, I tell students that this course is likely to be very different from any other mathematics course they’ve taken. The class is designed so that students learn from and with each other, not directly from me; I spend almost no time lecturing. Instead, the students work in small groups on a set of mathematical tasks during each class period. I’ve designed the tasks to pique curiosity and encourage students to make conjectures and look for patterns—in other words, the tasks are designed to engage students in doing mathematics the way that professional mathematicians do mathematics.

We basically spend almost all two hours of our time together doing math. I interrupt the work from time to time to facilitate students sharing their observations with each other. We close out the time by having a whole-class discussion and share-out about the (1) questions that we’re still wondering about, (2) interesting mathematical observations that we made, and (3) our gratitude toward one another for the contributions that they made to our learning.

Why number theory? Number theory is a wonderful area of mathematics that has a low threshold for entry and high ceiling for exploration. I have designed the course materials so that only experience with high school Algebra is required. Also, I am not at all an expert in number theory, so that allows me to approach things with a fresh perspective and to be surprised along with my students.

What’s it been like so far? We’ve already had four class sessions. We started by looking at the divisors of numbers and we’re currently thinking about modular arithmetic. Both the inside and outside students have been fantastic. Everyone seems to be deeply engaged in the mathematics and in working with each other.

Ideally, I would have had an equal number of inside and outside students, but right now I have 4 outside students and 15 inside students. We have been arranging ourselves in four groups of 4-5 students. This has worked out really well so far.

Unpredictable things happen all the time that prevent people from attending class. For example, during the first class session, parts of the prison were on lock-down so some students were not able to get to class. I have to be flexible and find ways to fold in students when they are able to attend class.


I hope to write more about my experiences throughout this semester. These are just some preliminary thoughts that I wanted to jot down.

This teaching and learning experience would not be possible without (1) the training and support I received in May 2018 from the Inside-Out Program, (2) support from administrators at the CRC, (3) the amazing students that are currently in the course, (4) and logistical support from the Claremont Colleges, made possible in part by a grant from the Andrew Mellon Foundation.

Next… Part 2

5 thoughts on “An Inside-Out Course on Number Theory (Pt 1)

  1. Thank you Darryl for all that you do and for sharing your experiences. You are an outstanding teacher and writer. I need to catch up on older posts.

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