How Henri Picciotto Designs Great Lessons

Learning from one of the best to ever do it.

My first contact with Henri Picciotto was August 2011, the summer after I’d started teaching, when he accepted my request to join his online “Escape the Textbook!” community. (Kids, ask your parents about listservs.)

This is Henri, photo from his site.

I didn’t really care about escaping my textbook at the time. There were only two math teachers at my school, me and the department chair. When I got hired, the department chair mailed me two huge AMSCO textbooks, a red and a blue one. These books were nothing more than examples and practice. I was fresh out of college and teaching for the first time—AMSCO did not tell me what I needed to know. Great, I’d escaped the textbook: now what?

You’re crazy for this one, Amsco.

What brought me to the group was Henri. I’d come across his essays about teaching and wanted to learn more. When I joined his community, Henri asked about my teaching responsibilities and wished me luck on my second year. (“If you’re like everyone else, it’s sure to be better than the first!”) Then he encouraged me to check out his website, where he’d shared “lots of free stuff, some of which may be useful.”

Fifteen years later, I’ve gotten rid of my AMSCO texts, but I’m still using Henri’s materials. In May, I used his Map Coloring activity with my 3^rd Graders. Henri’s Geometry Labs sheets are especially wonderful—this year my 7^th Graders learned about polygon angles from them.

What makes Henri’s activities work so well? I’ve found myself asking this often. Here is what I can currently point to.

A Single Set of Instructions

I’ve used Henri’s “Clock Angles” activity in both elementary, middle, and high school. The instructions are simple: draw hands on the clock to represent times. Don’t forget that the minute hand moves over the course of an hour!

It’s not hard to imagine a more finicky version of this activity. “Draw 5:00.” “Draw 5:30.” “Where is the hour hand at 5:30?” and so on. This might help us feel confident that the student will encounter important ideas, but with a cost—it’s taxing to read new instructions, and it interrupts some of the fun and flow of the core puzzle.

Another example of a single set of instructions, from Henri’s Map Coloring pages:

One of my favorite essays by Henri is “Nothing Works.” He argues for non-dogmatism about teaching, as the job is too varied to allow for principled consistency. I think that’s right. Many of Henri’s activities in Geometry Labs have multiple questions or sets of instructions, and at times that’s the right move. But when you can get away a single prompt that generates rich mathematical activity, that’s definitely the way to go.

Heading Towards Generalization

“Number Pyramids” are now fairly widespread in math curricula. I’ve seen them in the Beast Academy books and on NRICH. What makes Henri’s version stand out is his middle stance between exploration and explicit instruction. It’s only midway through the activity that a student might realize they’re in the presence of an interesting mathematical generalization.

Sometimes he interrupts an activity with a little STOP sign to ensure that students pause and reach for a generalization, as in his fantastic lesson on simplifying radicals.

Henri’s activities are consistently oriented towards a single meaningful, interesting mathematical idea. Sometimes these are conventional theorems or formulas, such as the polygon interior angle sum. At other times, as in Number Pyramids, the realization will never show up on any test. But these materials reflect a belief that what makes mathematics joyful isn’t just discovery—it’s about the pleasure of understanding. This value comes through in much of his work.

A Teacher’s Eye for Design

None of this would matter if it weren’t for something more prosaic: the materials are easy to use. This reflects Henri’s years of experience as a classroom teacher.

I often find myself reformatting materials before class. I add white space. I clarify questions. I make new diagrams, or have to replace confusing contexts. This happens even more often with mathematically rich materials, as designers with command of advanced mathematics rarely also have experience teaching young children.

Henri, however, has taught elementary, middle, and high school students. His pages reflect a teacher’s perspective on curriculum design. Every activity is contained on one or two pages, so they print nicely. There is ample room for students. He often includes blank tables that help students organize their results. There are discussion questions (useful for the teacher) included in the student materials, which makes it easier to guide the session.

You can see this in his “Polyomino Perimeter and Area” activity—his materials are classroom ready.

I’ve been teaching since 2010, writing about teaching since 2011. It has occurred to me, once or twice, that this is unusual. Most people who write or design interesting materials do it from outside of schools.

I have no doubt that I’ll be drawing on Henri’s materials in my teaching next year, and for many years to come. I’m glad that I’ve had to chance to be part of Henri’s communities, and grateful that someone with Henri’s many and varied talents ended up in teaching. When I think about the kind of classroom career I’d like to have, I think of Henri.

Henri—thank you!

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A short story I wrote appeared on the longlist for Wigleaf’s Top 50 [very] short fictions of 2025. They won’t tell me if I was #51 or #52 or what. No, seriously, it’s cool to be on that list. Check out all the other stories on the Top 50, like this one. In the middle of writing the last sentence I got an email that a different story of mine got rejected.

Do you want to hang out with math teachers online?? Join the Discord. One member of the Discord who was only slightly pressured for a quote called it “a dynamic space, full of educators who want to engage and reflect.” Wow, thank you anonymous member of the Discord.