All posts by Samuel Coskey

The BMC is now recruiting for 2017–18

Please apply for the 2017–18 Boise Math Circle program! The BMC is open to middle and high school students with some experience in algebra. If you like solving problems and want to learn more about the creative side of math, please consider applying. If you have a friend that does, invite them to apply too!

We are excited to announce one small change to our program. If you are familiar with our sessions, we generally spend all 90 minutes on an in-depth exploration. This Fall, we will begin each session with a quick introduction to a major concept in math, and then proceed with a closely related exploration afterwards. This means participants will learn or review key concepts such as modular arithmetic, matrices, enumerations, logic, and more!

We will begin on Saturday morning, September 2, and meet 15 times during the school year. See our schedule of meeting dates.


Please help us recruit participants by letting your students know about the program. If you’d like attendance reports for your students (e.g., for extra credit), please send us an email. You’re of course welcome to join the sessions.

Adding together infinitely many numbers

It is often necessary to add more than two numbers together. For example, you might have made 137 deposits to your bank account this year, and wonder how much you contributed in total. But is it possible to add infinitely many numbers together? The answer is that sometimes it is possible, and sometimes it isn’t! In this discussion we investigated when, why, and how! Continue reading Adding together infinitely many numbers

Boise Math Teachers’ Circle recruiting for 2016-2017

The Boise Math Teachers’ Circle is excited to announce our program for the 2016–17 school year! The BMTC is open to K–12 mathematics educators. We will meet four Saturdays, for four hours each, to discover exciting math concepts and tackle challenging math problems together.

Our session dates

  • Saturday, October 22, 2016
  • Saturday, January 21, 2017
  • Saturday, February 25, 2017
  • Saturday, April 15, 2017

Ovals upon ovals!

A circle has a center c and a radius r. The points on the circle are all a distance of exactly r units from c. What if we start with two fixed center points? The set of points on an ellipse have a fixed sum-distance to two center points c1 and c2 (called foci). An ellipse has kind of an oval shape. Ellipses occur in nature – the Earth’s orbit is not a perfect circle but rather an ellipse, with the Sun being just one of the two foci.

In this activity we investigated how to draw ellipses using pushpins and string. We also asked whether it is possible to have more than two fixed center points. Continue reading Ovals upon ovals!