Vehicle Chat [Invitation]

It all started with a disagreement between Kassia Wedekind and her daughter Lulu.

Pretty soon, it wasn’t just elevators we were arguing about, and it wasn’t just Kassia and Lulu weighing in. #vehiclechat was born.

With Math On-A-Stick on the horizon, I put together a prototype concept book, and now I am here to report to you what I have learned from many dozens of conversations about the nature of vehicles.

The book begins with some easy, quick decisions. Dump truck? Yes. Salad? No. (Usually. More on this below.) Airplane? Of course! Next up are increasingly controversial cases, including elevator, horse, and broken-down bus with no wheels.

image credit: Don O’Brien on, licensed CC-BY

There are about a dozen subconcepts pertaining to vehicles that people carry around in their heads, but which most people have never spoken out loud. Some of these subconcepts are in conflict with each other; some are independent of each other. Some people cling tightly to one or two of them; others loosely hold four or five.

Here are some examples, in no particular order:

  1. Vehicles carry people (not just things).
  2. Vehicles must have wheels.
  3. No living things are vehicles.
  4. Vehicles take people or things from Point A to Point B. (And then there is 4a. Point A and Point B must be different points from each other.)
  5. Vehicles must have an engine, motor, or some other dedicated power source.
  6. A vehicle must have—as its designed and primary purpose—transportation across the surface of the Earth.
  7. Once a vehicle; always a vehicle.
  8. If it could be a vehicle, with a little work or repair, then it is now a vehicle.

One thing we know about math learning is that we nearly always work from examples and mental images of things rather than from logical definitions of things. This is why you can have a second grader tell you in all earnestness that a triangle is a shape with three sides, and also tell you that the image below is not a triangle because it doesn’t look like one.

Knowing a definition (three-sided shape) doesn’t guarantee that you’ll use that definition for naming things. A classic paper by Vinner and Tall details this disconnect as being about concept image and concept definition, and it’s related to Kahneman’s Thinking Fast and Slow. Concept images are the tools of the fast judging brain, while concept definitions are the tools of slow analytical mind.

Somewhere into those controversial cases, there is one that makes everybody think. It’s not the same example for everyone, but each person has at least one. My vehicular conversation partner and I will cruise past airplane and tricycle, and then they will pause and smile and look off into the middle distance. That moment is the one I seek—when you notice that your quick reactions aren’t good enough and now it’s time to think—even if only for a brief moment.

Also I have learned that metaphorical examples are more comfortable for many people than close, but not-quite-right examples. This means that I’ll often hear a quick “Yes” to salad (a vehicle for nutrients into my body), but a slow “Yes” or even a “No” to elevator (because it doesn’t have obvious wheels, or has a limited range of travel, or for some other reason). 

Most of all, I have learned that these conversations are really a lot of fun. People smile. They laugh. They think of additional challenging examples. They ask “What about?” and “What if?” They imagine what other people might say, and why particular examples might be controversial.

This is a social game of negotiating meaning, and of noticing that language which seems so precise is often not that at all. Play along with us! Offer up some examples in the comments, or some additional vehicle subconcepts not listed above. Or join the conversation on Twitter.

Book Launch Party Tuesday!

A new version of How Many? is coming out on Tuesday, from Charlesbridge. It has an all new design, some new words, and mostly the same images, but is published for the home market. (Whereas Stenhouse publishes primarily for the teacher professional development market, and so is still the place to pick up the teacher guide.)

Charlesbridge did a lovely job with Which One Doesn’t Belong? earlier this year, and this one has come out beautifully as well. Both have been well reviewed in Kirkus Reviews.

And we’re celebrating with a launch party at the Red Balloon here in Saint Paul, MN. Tuesday, September 10 at 6:30 p.m. (The Red Balloon is on Grand Avenue, just west of Victoria.)

We’d love to have you join us! We’ll count and play with math toys and maybe even chat about vehicles!

Talking Patterns with Kids

I am working on another book; this one will be about patterns.

That means I need to learn about how people learn about patterns, and that means going to school.

So yesterday I packed a collection of images and asked 3rd, 4th, and 5th graders what patterns they saw.

Turtles are based on a Jos Leys and Kevin Lee image. The basket is on display at the Museum of Fine Arts in Boston.

Of course they blew me away. Perhaps a favorite moment was when a fifth grader told me that each turtle made space for another turtle, and that also each turtle needed the other turtles to make space for it.

Across the images, these students saw repeating and growing patterns. They saw patterns involving shapes, colors, numbers, and combinations of all of these.

I encourage you, the reader, to take some time with some children and ask each other these questions:

  • What patterns do you see?
  • So what repeats?
  • How does it repeat?

Then report back. Let’s learn together.

In the meantime, you should know that a new version of Which One Doesn’t Belong? came out this week. Same shapes as the original, new book design, new colors, and a few new words. Importantly, this is the first in a series of collaborations between Charlesbridge and Stenhouse by which a home version of each Stenhouse book is issued by Charlesbridge about a year after first publication.

Look for it (or even better…ASK for it) at your favorite bookseller.

Which Poster Doesn’t Belong?

(Cross-posted from Overthinking My Teaching)

Two and a half years ago, I was developing Which One Doesn’t Belong? (before Stenhouse had signed on to publish it). I went on a tour of elementary classrooms to talk with K—5 students all around the Twin Cities about these collections of shapes. I learned a tremendous amount of course, and much of that learning went into the Teacher Guide (which Stenhouse convinced me needed to exist).

I learned a lot, and I also noticed something.

Most of those classrooms had some form of shapes posters on the walls. Triangles, rectangles, squares, and rhombi were proudly and prominently displayed so that students would be surrounded by correct geometry vocabulary. Most of those shapes posters had something important (and unfortunate) in common with the shapes books in the school library and in the children’s homes.

There were rarely squares on the rectangle poster. All of the triangles were oriented with one side parallel to the ground, and most of them were equilateral. Sometimes the shapes had smiley faces. You and I know that a triangle is still a triangle, no matter its orientation. I can assure you not all elementary school children know this. While the vocabulary is good on your standard shapes poster, the math is not. (I decided not to link to examples—you can do your own search and report back if you find my claims exaggerated.)

This summer, Stenhouse is helping all of us to fix this. You can now preorder Which One Doesn’t Belong? shapes posters.

Poster images

They come as a set of eight, with an insert in the spirit of the Which One Doesn’t Belong? Teacher Guide to help you facilitate student thinking and classroom conversation as they hang in your classroom.

1. Which SQUARE doesn’t belong?

2. Which RECTANGLE doesn’t belong?

3. Which RHOMBUS doesn’t belong?

4. Which HEXAGON doesn’t belong?

5. Which TRIANGLE doesn’t belong?

6. Which POLYGON doesn’t belong?

7. Which SHAPE doesn’t belong?

8. Which CURVE doesn’t belong?

These posters are filled with good mathematics. Consider the triangle poster on top of the pile. The triangle in the lower right is the only right triangle. The one in the upper right is the only equilateral triangle. The one in the upper left is the only isosceles triangle (or is it? do equilateral triangles count as isosceles?) The one in the lower left is the only one you can’t build out of the triangle in the lower right. Students will notice side lengths, angle measures, orientation, composition and decomposition, and more properties of triangles. Some will complain that not all of them are triangles (“too pointy” or “doesn’t have a bottom”). These posters let you and your students sit with—and play with—these ideas over a period of weeks or months.

So as you plan your back-to-school classroom organizing and decoration, I hope you’ll consider making space on your walls for these posters. And I definitely hope you’ll share your students’ ideas here and on Twitter.

Available for pre-order now. They’ll ship in early August.

A delightful new book on Kickstarter

There are a bunch of people doing really good and interesting work with math and kids these days. Sasha Fradkin is one of these. She has a gift for tapping deep into kids’ mathematical minds and for writing about the beautiful ideas she finds there.

She has written a book—Funville Adventures—that is definitely worth your time and money, and she’s funding its publication on Kickstarter. I have pledged. You should too. I promise you’ll be glad you did.

National Math Festival

I’m taking Math On-A-Stick and Which One Doesn’t Belong? on the road—to the National Math Festival in Washington, DC on Saturday, April 22, 2017. If you’re nearby, you should come out and say Hi!

I have two Math On-A-Stick sessions—at 10:00 and 4:30—and one Which One Doesn’t Belong? session at 2:30. The Math On-A-Stick sessions are pure play; the Which One Doesn’t Belong? one is interactive but more talky.

There are lots of other amazing folks doing amazing things with all ages, so come spend the day! It’s free. See you there.

The Summer of Math is back!

We had so much fun the first time around, the Summer of Math is back for a second year, and it has its own webpage!

The basics are the same as last year:

You can head over to The Summer of Math webpage, pay for a subscription, and all summer long (June—August) we’ll ship you awesome, fun stuff that will keep you and your 5—10 year old(s) busy playing and talking math.

You’ll color, count, make patterns, designs and shapes. You’ll read together, draw, and challenge yourselves. You’ll notice. You’ll wonder. You’ll play. And when school starts back up in the fall,

your kids will remember this as the best, mathiest summer ever.

A few small changes include: a new website, three boxes instead of four (but same amount of total mathy goodness, so the net result is higher math-fun density in each box), and a few new things rotated into the lineup (the Truchet tiles are curvy this year!)

Together with a little help from some super smart friends, we’re shooting for a bigger Summer of Math this year, but there is an upper limit on subscriptions. Help us reach it—and as many families as possible—by signing up and by spreading the word.

Fractivities! Coming soon to a school near you! (If you issue the invitation.)

New to Minnesota, Jennifer Schuetz from the Fractal Foundation brought fun fractal activities, or fractivities, to Math On-A-Stick last summer.
Younger students had the opportunity to learn how the Sierpinski triangle is a fractal – by repeating a simple pattern over and over again, smaller versions of the same pattern are created.
Older students created their own Sierpinski triangles with wooden sticks and glitter glue to make a fractal with sticks!
With help from Minneapolis High School art teacher Stephanie Woldom and math teacher Morgan Fierst, we had tons of fractal fun with hundreds of children and their parents from across Minnesota!
Jennifer’s dream turned into reality: job title of visiting artist/mathematician!

Jennifer leads fractal education in classrooms and other venues across Minnesota, the U.S. and the world (her geographic reach is ever-expanding just like fractals!). Fractals are not only appealing to children but also adults… even senior citizens have fun learning about them!

Instructions to 12 fractivities and associated worksheets and answer keys are at:

What do you think about projecting videos of fractal zooms accompanied to original music onto the dome of a planetarium? The Fractal Foundation also does this! More information can be found at:

You can also get in touch with Jennifer to see how to do this. Check out some videos at:

Finally, Jennifer is looking for gigs in schools! Get in touch through the Fractal Foundation Facebook page.

Boxes of Math are here

I and dozens of families across the US, Canada, and England had a blast with the Summer of Math last summer, and now I’m gearing up for the school year version: Boxes of Math.

Starting small with a single option for kindergarten and first grade (five- and six-year-olds, roughly), Boxes of Math will have some overlap with last summer’s Summer of Math, but are targeted at this more narrow age range and the math they’re learning in school.

Boxes of Math consists of:

• A small welcome and introductory shipment before the New Year

• A box for counting and patterning in mid-January

• A box for shape study in late February

• A box for number structures and operations in late March/early April

Each box will have a book, one or more things to get your hands on, and a newsletter with ideas about fun ways to play and to continue the learning in your everyday lives.

Why Boxes of Math?

Inside these boxes are things that help create conversations. They get children thinking about the most important ideas of elementary math.


A few of the objects that will fill the boxes of math.

Most children who struggle with math later on aren’t familiar with these ideas. They know facts by rote, but not in relation to each other. Or they cannot retain the facts because they see no relationships. They can name triangles, but don’t see all polygons as made out of triangles. They can count large numbers of objects fluently, but they don’t notice whether these objects are arranged in rows and columns.

Those are the things this website is all about.

Struggling or not, all children benefit from exercising their math minds through play and conversation.

Boxes of Math offers children and caregivers opportunities to play, experiment, and talk in ways that bring these ideas to life. Noticing rows and columns is a natural outcome of playing with pattern machines. Playing with 21st Century Pattern Blocks is an extended exercise in putting shapes together and taking them apart.

The target outcome of Boxes of Math is children (and families) with a similar relationship to math as they have to literature. They talk about it, see it in their world, and use it to understand their lives in richer, more beautiful ways than before.

Sign up, give it as a gift, pass the word on to friends and neighbors, won’t you?