366 Days of Math

Look at your day. Really look at it. Have you noticed a small hole in your existence? A gap in the fabric of your life?

A daily gap whose dimensions are, say, 5 inches by 7 inches?

I know what you’re missing. It’s the new American Mathematical Society page-a-day calendar, the brainchild of witty and trenchant math writer Evelyn Lamb.


I got my hands on a copy last month and found myself reading January and February like a book: a quirky, brainy, immaculately researched book that you slowly tear apart as you read it. (Note: I do this with more books than I should.)

I asked Evelyn to tell this calendar’s story.

How did this project begin?

A friend of mine called me out of the blue and asked whether I knew of a math page-a-day calendar and if I didn’t, did it sound like a good idea?

I hadn’t, and it did!


Why a calendar, rather than a 366-page book of mathematical goodies?

I’ve thought about writing books. One possibility would be a compilation of posts from my blog Roots of Unity. (Publishers, talk to me if that’s something you’re interested in!)

But I’ve not quite found the right way to organize something that eclectic. With the calendar, I don’t really mind that there’s no big narrative arc. I just want to give people something interesting related to math every day!


Eclectic it is! We get puzzles, art, Sudoku variants, jokes, recipes, history, music, conjectures, coloring pages, quotations, poetry, theorems… did I miss anything?

There are hands-on activity pages too, that involve cutting or folding the page. Also, there are quite a few pages about different number systems, like the base twenty system developed by Inupiat students in Alaska to make it easier to do arithmetic using their native language.


It’s deliberately reusable, with no reference to the year (e.g., no days of the week). Did that increase the level of difficulty?

AMS books don’t usually have expiration dates; if they misjudged the size of the print run, they’d be stuck with a lot of product they couldn’t sell. Unfortunately, that did make it tricky to include things like Mother’s/Father’s Days, Hanukkah, Easter, and other holidays that don’t fall on the same date every year. But they were committed to the idea, so I grudgingly went with it.

In the end I’m glad we did. The calendar was initially intended for 2019. (Everything takes longer than you think it will!) So I would have had a lot of work to redo when it took an extra year to finish. Also, now that I know how much work this calendar was, I’d like for it to be out there for at least a few years.


How did you handle holidays that change dates from year to year? And what about Leap Day?

For some of the holidays that move around from year to year, I put the relevant page on the first possible day. (E.g., there’s a vaguely turkey-looking coloring page on November 22, which is the earliest possible date of U.S. Thanksgiving.) For some, I put it on the day the holiday would occur in 2020. And for some, I just put it vaguely near the right day.

And don’t worry! The February 29 page is actually a flowchart so you can determine whether the February 29 page is needed.


I’m impressed at the depth of research.

I joked a bit with my spouse about this being a very inefficient project in some ways. I read two academic books about khipus to make one 5×7-inch calendar page!

How did you figure out the right date for each morsel? Conspiracy wall full of newsprint and red string?

It was a bit of a conspiracy wall!

I had a file on my computer called “calendar date thing” (I am great at file names!) where I kept track of where I had coloring pages, different types of puzzles, birthdays, Pi Days (there’s one per month), art, and so on. I wanted to avoid clumping things too much.

There ended up being a lot of shuffling because I’d write a page, put it on some arbitrary date, and then find someone whose birthday was that day, so I’d have to shift things around. I definitely made it harder than necessary, but it was also a fun puzzle.


How did you decide which people to celebrate?

I made a lot of rules for myself. There are six biography pages a month, and they are all about dead people (because I thought it would be weird for a living person to read a page about themselves).

For most, the pages are on their birthdays. I thought putting them on an anniversary of their death would be too depressing (though I did make Hausdorff’s depressing; he committed suicide rather than be taken to a concentration camp, and we should be sad about that).


Half of the biography pages are about men, and half are about women. I did my best to keep this balance each month as well. (I might have a couple months with four and two, because people rudely chose not to be born on days that are equally distributed throughout the year!) I worked at having a lot of racial/ethnic diversity, though I didn’t set myself any explicit number goals for that.

I included some mathematicians who are really well known (hi, Gauss!), but I also wanted to include people I had never heard of before, or people who might not be thought of as mathematicians but had some math connections in their lives, like W. E. B. Du Bois, James Garfield, and Anna Julia Cooper.

I thought about including some people who really sucked (and writing about how much they sucked) like Oswald Teichmüller, an actual Nazi, but decided I wanted to focus on more admirable people, like Lee Lorch, who got fired from multiple jobs for his civil rights activism, or Thyrsa Frazier Svager: she and her husband saved about half of their income to create scholarships for black women math majors.


Anything I didn’t ask about?

It’s so funny you picked February 6th to share above, because when I first flipped through the final calendar, I looked at that page—which, like all the pages, I had read through maybe a dozen times already—and thought, “This page makes no sense!” This is more a converse to Poincaré’s quote: different names for the same thing. But hopefully people will just think I’m trolling them. (In general, please assume I’m playing an elaborate prank if and when you see errors in this calendar.)

Anyway, thanks for letting me ramble on about my baby! I’m very proud of this project.

For anyone who’s bought one or gets one as a gift, I’ll be at the Joint Math Meetings in Denver in January, and I’d be happy to sign your birthday page or other important date.

And I’d love to chat with you about the calendar as you’re enjoying it next year. You can find me on Twitter: @evelynjlamb.

You can buy the calendar through the American Mathematical Society.

7 thoughts on “366 Days of Math

  1. “(In general, please assume I’m playing an elaborate prank if and when you see errors in this calendar.)”

    November 4th: the number 123456789 should actually be 12345679. Yeah, that’s probably just an elaborate prank, not a mistake. 🙂

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