CLASSIFIED MATH

Public Math is running classified ads in The Monitor, the neighborhood paper of Midway, Como, and Frogtown in Saint Paul, MN. This paper is delivered monthly to every residence in these neighborhoods, and classified ads cost $1 per word (10-word minimum). Do you have such a paper in your community? Reach out! Let’s collaborate on getting more math into more homes!

October 2025

How is a coffee cup like a donut?

There might be lots of ways, but mathematicians who study topology would say that they each have exactly one hole. The hole in the donut is obvious. The hole in the coffee cup isn’t where you pour the coffee, it’s the handle! For more of this kind of thinking, click on through to the Which One Doesn’t Belong? website. You’ll find a coffee cup and a donut paired with two edible companions on the Photos page.