Loop-de-Loops! And a contest!

As some of you might know, I recently wrote a book!

Cover image
Credit: Kane Miller Publishing

It’s a math and art activity book, containing all of the amazing MArTH activities developed by me and the Saint Ann’s School math department over the five years that I taught there. There are more than 30 different activities in the book, ranging from favorites like Pascal’s Triangle coloring to things you may not have seen before, like the Stomachion puzzle. I had SO MUCH FUN writing it– and I hope that someone out there has as much fun using it and I did putting it together.

(If you’d like to browse the book and maybe even buy one, click here.)

I’m posting this week not just to make this announcement, but because of an exciting opportunity! Dan Meyer had the amazing idea to run a contest for teachers and their students on his blog featuring one of my favorite activities from the book– Loop-de-Loops.

Credit: Kane Miller Publishing

Visit Dan’s blog to find out more about the contest! In a nutshell, it involves making Loop-de-Loops with your math class, sending them to Dan, and some math art friends of Dan’s choosing their favorite loop. You and your students could win a class set of This Is Not a Math Books!

Now, say you’re a teacher thinking of making Loop-de-Loops with your students, hopefully to enter Dan’s contest. Say you’re also wondering, what else can I do with Loop-de-Loops other than just have my students draw some? That’s a fun, mathematically interesting activity on its own– and I’m sure your students will have a blast if you stick to that. But say you wanted more…

So, for the next few posts, I’ll be sharing some more mathematically rich things you and your students can do with Loop-de-Loops. The first is pretty simple. I call it “Detective Loop-de-Loop.”

It’s one thing to come up with your own number sequence (like 2, 3, 4) and make a Loop-de-Loop out of it. It’s another thing entirely to look at a Loop-de-Loop and figure out what number sequence was used to create it!

1 3 6 LoopFor instance, what number sequence made this Loop-de-Loop? (Hint: It had three digits.) This one is easy compared to…

2 3 4 5 6 Loop(Hint: This one uses five digits!) Figuring out how a Loop-de-Loop was made requires looking for patterns, thinking backwards, and checking your hunches with a diagram– all math habits of mind that are important for elementary and middle school students.

“Detective Loop-de-Loop” doesn’t have to stop with deciphering and trying to recreate tricky Loop-de-Loops. Lots of interesting questions come up. Like…

Dual 2 3 4 and 2 4 3 LoopsThese two Loop-de-Loops look pretty similar– the only difference is that they seem to be looping in different directions, one clockwise and the other counter-clockwise. How were they made? What difference between their number sequences caused them to have different “chirality,” which is the technical math and science term for the direction something rotates?

Once you start making Loop-de-Loops and playing Detective Loop-de-Loop, you’ll notice that there are many interesting questions to ask about how different loops were made– and why small changes in the number sequence behind a loop make such big changes in the way the loop looks.

3 2 5 Loop

Or doesn’t… Here’s a 3-2-5 Loop-de-Loop. What would a 2-5-3 Loop-de-Loop look like? How would it be different, if at all? Can we figure out how to make a Loop-de-Loop that looks exactly like the 3-2-5, but turns in the opposite direction?

I think Loop-de-Loops are rich mathematical objects– meaning that playing with them can lead to an enormous number of interesting questions and investigations that take you and your students into the worlds of geometry, number theory, patterns, functions and more. Even just making up your own Loop-de-Loops and playing Detective Loop-de-Loop presents many opportunities for students to wonder about math and use their wondering to create something beautiful.

You can print these Loop-de-Loops for you and your students to play Detective Loop-de-Loop with. But you should also make more of your own– it’s fun, so why not?

To wrap up, I’ll give you a starters’ list of interesting questions to investigate while you and your students make and play detective with Loop-de-Loops. Of course, you might not use any of them– you might have so much fun drawing, coloring, and decorating your loops for Dan’s contest that you forget all about questions. And that’s great, too! Math class needs more time for free creativity, in which kids can feel proud of what they’ve made. At least, that’s what I think.

2 5 3 6 2 LoopInteresting questions:

  • What different number sequences make identical Loop-de-Loops? What do these sequences have in common?
  • What different number sequences make Loop-de-Loops with opposite chirality? What patterns can you find in those sequences?
  • 2 4 3 3 5 LoopWhat kinds of number sequences make Loop-de-Loops with long arms, like the first one in this post, or that are tightly packed, like the loop to the right? What about the sequences causes this difference?
  • Have you made a Loop-de-Loop that surprised you? What about it was surprising?

Post your loop drawings and classroom activity ideas in the comments section! Don’t forget to enter Dan’s contest, and have a lovely loopy day!



Assessing the Un-Testable

I think I mentioned the Talking Right Past Each Other Paradox in my last post. It’s the problem that some education researchers see where they want to do research that helps teachers, but they feel like teachers aren’t reading their work. At the same time, teachers have problems that they could use some help with—and it’s nice to have someone with lots of time to think about your problem give suggestions. But the suggestions don’t always come. Hence, Talking Right Past Each Other.

I had an encounter with said Paradox the other day in one of my classes. We were reading an article that another grad student (Kyle) picked out about “epistemic cognition.” If you feel like spending a half hour with your dictionary, by all means skip my so-so definition of epistemic cognition. If you’d rather not, here’s what I think it is: what people think about knowledge and learning.

The article was about the problems researchers have with figuring out exactly what people think about knowledge and learning. Researchers want to figure this out because they’d like to have a clear trajectory of the development of people’s thoughts about knowledge and learning, tracked as people get older and learn more about particular subjects. Researchers would also just like to be able to assess what people are thinking so that they can help them think better things. Thoughts about knowledge and learning have a lot to do with how you actually learn, so it would be nice to know what you’re thinking about what you’re learning to help you learn it better.

All of this makes sense. From the article, I could also clearly see how the researchers were having problems with their ways of assessing epistemic cognition. I won’t go into that (by all means look it up, it was interesting: by Greene and Yu, called, “Modeling and measuring epistemic cognition: A qualitative re-investigation”). But this was about as far as my thinking went. First, I agree that it’s useful to know about what people think about knowledge and learning. Second, I see how those researchers could be having a hard time.

We were wrapping up the class when Kyle made a comment that jogged my brain. To close the discussion, he said something about how he hopes that researchers figure out how to measure epistemic cognition. I hadn’t had that thought. So I asked him why—why did he hope that researchers figured out how to measure epistemic cognition? His reply was so that he could do a better job of teaching. He wants his students to have nuanced and well-rounded ideas about knowledge and learning, and he felt like have a research-proven, efficient test for epistemic cognition would be helpful.

Somehow this didn’t make sense to me. I mean, it does make sense—I suppose a test for epistemic cognition would be awesome. But I was having two problems. First off, I couldn’t picture what a closed test of epistemic cognition—one that you could administer within one day—would be like. I really don’t know enough about designing epistemic cognition assessments to know, though. The second problem was the bigger one. Even if someone did come up with a test that measures epistemic cognition, I couldn’t see myself using one in a classroom in a natural way.

It’s not like I didn’t keep track of what my students were thinking about knowledge and learning while I was teaching. In fact, helping my students develop a particular set of thoughts about and attitudes towards math knowledge and learning was a major focus of my teaching. And I totally assessed it. I just didn’t give a one-off test for it.

I did raise these complaints in class. (Case-in-point of me being a terrible student—being argumentative right at the end of class.) We talked about them a bit, and then the professor asked Kyle whether he assessed epistemic cognition when he was teaching. Kyle said he did. How did he do it? Kyle thought for a moment and answered, by seeing what kinds of questions his students asked.

Yeah, I thought, that’s partly how I did it, too. I think that works really well. When kids ask probing, authority-challenging, curiosity-sparking questions, that shows they have top-notch epistemic cognition. (Not sure if “top-notch” is a correct measure of epistemic cognition, but oh well.) Kyle seemed to think that this way of measuring epistemic cognition worked really well, too.

But kids don’t ask their awesome, top-notch-epistemic-cognition questions all at the same time. They don’t even do it all the time, even if they do have that cream-of-the-crop epistemic cognition. That’s just not how it works. Sure, the fewer awesome questions they ask, the more likely it is that they think that knowledge is something you pour into brains. (Or that the teacher’s class isn’t open enough to students’ ideas.) But there’s also a personality thing. And the fact that asking awesome questions isn’t easy, even if you do have glorious epistemic cognition. And the fact that kids strut their epistemic cognition stuff in the context of class itself, not on a test that’s just about epistemic cognition.

So can you—should you—turn Kyle’s question-asking way of measuring epistemic cognition into a closed assessment? Would it still work in a real-live classroom full of real-live kids? If I’m trying to teaching my students robust ways of thinking about knowledge and learning, is closed, fast assessment the part I really want help with? I don’t know! But here we go again, Talking Right Past Each Other.

I’m not saying that there’s anything wrong with researching a tool for measuring epistemic cognition. It’s an interesting problem. But I don’t know if it’s the most interesting question about epistemic cognition from a teaching perspective. I think the discussion we had, as thoughtful folks straddling the divide between teaching and research, demonstrates that very well.

There Are No Kids Here

I took a bit of a break from writing because I’m actually not teaching at Saint Ann’s anymore! I started a Ph.D. program in math education at UC Berkeley in September, so the past six months have been consumed with homework, readings, papers—that sort of thing. The first thing I’ll say about that is that while teaching, I have definitely become I worse student. I hear this is common. If anyone would like to do some research on the terrible students that former teachers become, I volunteer myself as a case-study.

I’m writing again for two reasons. First of all, I re-found a great education blog by someone who is also on the other side—Ilana Horn! I was in the middle of a small bout of despair about education writing when I re-found her blog. I have small bouts of despair about things related to education research every now and then, and this one was sparked by what I’ll call the Talking Right Past Each Other Paradox: Education researchers say their main goal is to help teachers, but they feel like their work doesn’t often get read by teachers. My first thought when I heard this was, “Because the researchers don’t blog about it!” And then I remembered that one of them does blog about it! And I realized that it is possible to write something about education research in a human, intriguing, and useful way. And I wanted in.

I’m obviously not ready to do this on even 1% of the same level as Ilana—so that’s not really why I’m writing again. The second, and primary, reason why I’ve jumped back in is basically the same as why I started blogging in the first place—because I’m having teaching problems.

Just like I was totally unprepared to teach math to kiddos when I first started at Saint Ann’s (not the fault of a teacher prep program—I didn’t go to one), I am totally unprepared to teach teaching to college students. This also isn’t the fault of a teacher-teacher prep program, because there isn’t one. I’m really not sure why. It’s not like college students aren’t kids, too, who need care and personal attention. It’s also not like teacher educators have got the whole teaching thing figured out, either.

Anyway, a little back-story to my current teaching problem—I’ve been “TA-ing” and “researching” in an education class for undergrads who are in one of Berkeley’s teacher prep programs. But the other day, I was launched from my cozy position as TA to the much scarier position of actual teacher. The instructors didn’t have anything planned for an hour chunk of class and one of them was going to be late. So they pulled out their secret weapon, the TA, to fill in the gap.

What should I do with 40 pre-service teachers for an hour? I first approached the task like I would if they were 40 high school students with whom I was asked to share something cool and mathy. They’d just read some articles about inquiry learning, so I thought we could do a little math inquiry together. But then I realized that my lesson was missing something essential. I had a great math problem picked out. But they weren’t going to do any teaching. I didn’t have a “teaching problem.”

And this is when the sheer challenge of the task hit me. I needed a teaching problem—but there are no kids here.

If the material of math problems is math, then the material of teaching problems is kids, right? You use math to do math, and you use kids to do teaching. Sure, plenty of math problems you find are missing the “real math”—but if you dig around enough and know what you’re looking for, you’re sure to find something. But, search all you like, you will not find kids in this class.

You may now be wondering whether I’ve been paying attention at all during the last six months of grad school. Yes, I knew before yesterday that there are no kids in education grad school. And, yes, I have been reading my Pam Grossman and I know a bit about “approximations of practice” and that sort of thing. I knew that folks had already identified the lack of kids as a problem in courses about teaching. I guess it didn’t hit me how much of a challenge this really is for developing good activities for pre-service teachers until I had to develop one of my own.

I did come up with something to do with the pre-service teachers. It did not involve the miraculous appearance of kids. Like most spur-of-the-moment, first-time activities run by new teachers (because I’m definitely a new teacher now, as new as I’d be if I switched to teaching English), it didn’t go as planned. I want to try it again, with Round 1 under my belt, and then I’ll write about it. I’m not sure if it was any good.

Until then, though, I just wanted to reflect about this problem for myself and anyone who is interested. I also wanted to ask for help. Does anyone have any good teaching problems? I’m calling them that because it makes a parallel with math problems that’s helpful for me. I don’t want teaching exercises, I want teaching problems, ones that really make people think and engage with genuine teaching. If I tried my hardest to not give kids math exercises when I was a math teacher, I want to try my hardest not to give kids teaching exercises now that I’m a teaching teacher.

It seems like the task might be more difficult, though, because like I said, there are no kids here. That seems like a real problem to me.


Happy New Year! Enjoy this Sierpinstree we made for you.
photo (2)

In the week before we left for our Winter Break, the middle school math art classes, my 6th grade class, another teacher’s 4th grade class, and as many other students as I could round up drew and colored 243 Sierpinski Triangles. On the day before the last day of school, we spent two class periods taping them to the floor in the Undercroft (aka basement, where I have my classroom) to make an enormous Sierpinstree (that’s short for Sierpinski Triangle Christmas Tree). The tree is truly huge– it’s over 20 feet tall and about 28 feet wide. It covers the entire floor– though people could (and did) walk around without stepping on it by hopping in the holes.

IMG_5553As you might imagine, this was a very large and ambitious undertaking. Drawing that many Sierpinski Triangles is no easy feat. When I suggested the project to my classes, they jumped on it with enthusiasm. But, as you also might imagine, enthusiasm for the project waned once the students were 60 triangles in, with nearly 200 to go, and no end in sight…

I knew that this was going to happen. And, up until the last triangle was taped to the ground, I was fairly certain we weren’t going to finish. I knew that the kids were certainly capable of finishing the project– but would they be motivated enough to do so? Would they be able to keep the awesome goal in mind while slogging through the boring, but important, details? Would I be a good enough leader?

The conflict I had with one student highlights the concerns I had particularly dramatically. It was two days before we were due to assemble the triangle and we still only had about 80 of the 243 completed. Sometime in the beginning of class, this student calls out, “I hate this!” He was referring to drawing and coloring in Sierpinski Triangles. Now, this student is always especially vocal about his feelings and really doesn’t like being told what to do. His aversion to making Sierpinski Triangles was certainly stronger than the distaste felt by his classmates. But, when he refused to make any more triangles– and to help out in any of the other ways I suggested– the tone in the room shifted slightly. People began to complain a little more and cooperate with each other a little less.

I didn’t want to force him, or anyone else, to make Sierpinski Triangles. This project was only going to get done if the kids wanted to do it. Math art isn’t about forcing kids to make things– it’s about giving them space to explore and express their mathematical tastes, and to make things they care about. At the same time, however, as their teacher, I felt responsible for guiding them through the artistic (and mathematical) process. Often when you’re making a piece of art or mathematics, the grunt work isn’t very fun. But you do it anyway because synthesizing the details, putting together the big picture, and enjoying the results are so wonderful. I wanted them to learn to be long-sighted (opposite of short-sighted?) in their mathematical and artistic work, but not to cram it down their throats. This was a tricky balance to strike.

When the day of assembly came around, we had more than enough triangles. Seriously. And the building process was almost entirely organized by the kids. Some continued coloring and touching up unfinished triangles that we needed, others cut them out. Some took on building the bottom of the Sierpinstree, making sure that it actually fit on the floor, while others build the whole top third. They were enthusiastic about the project– and, even better, they cooperated. They were kind to each other, shared ideas and problems respectfully. Not a single person complained about the task they were set.

IMG_5535When it came down to it, when it was time for the fun synthesis and big-picture work, everyone wanted to participate and to make the project a success– even the particularly grouchy kid from two days before.

He was more cooperative than I’ve ever seen him. He worked with pride to color triangles and tape them down. He even stayed after class to keep working. When the project was done, he patrolled the perimeter, alternately beaming with pride and glowering at kids who he thought might step on the triangles.

This seemed like a good time for a little chat. I called him over, and was also joined by another student– one of the most agreeable kids I’ve ever met, who loves everything and everyone.

I asked the first kid how he was feeling. Did he have a good time today? “Yes!” he certainly did, and he was really happy with the Sierpinstree. Then I nudged him a little.

“Do you remember what you said the other day? When we were making the triangles in class?”

Unsurprisingly, he didn’t remember. The second kid helped jog his memory.

“You said, ‘I hate this!'” said the second kid.

The first kid looked thoughtful, and then a little sheepish. “I think I might remember that…”

I turned to the second kid. “Did you like making the triangles? Be honest.”

He wouldn’t hurt a fly, and certainly never my feelings, but he was honest: “No, not really. It was okay.”

“But you did it anyway and you didn’t complain.”

“Well, I wanted to make this!” he exclaimed, gesturing to the monstrous triangle on the floor. “Complaining doesn’t make anyone feel any better about drawing all those triangles. But we had to do it.”

I hardly had to say a thing. The first kid looked like he’d never thought about this before. He’ll probably do the same thing all over again later– probably when we’re doing our giant ZOME build in the spring. But at least I”ll have a powerful example (for him, for the other students, and for myself) of a time when we worked hard, cooperated, and made something awesome.



The various meanings of “I don’t know”

A series of events the other day struck a chord with me. They all centered on a simple little phrase, offered often enough in math class to not be unusual. That phrase is, “I don’t know.”

The first “I don’t know” came during my 6th grade class. A girl was stuck on a problem (building polygons with different numbers of sides out of as few triangles as you can). When I came over to see how she was doing, all she could say was, “I don’t know how to do this.” And, “I don’t know,” was quickly followed, as it often is, by, “I can’t do it.”

It’s funny how those two phrases so often go together. There’s no inherent reason why a student should think that just because he or she doesn’t know something right now, he or she will never know it. I mean, this is school. You’re supposed to be learning about and figuring out things you don’t already know. And I’ve seen this particular girl puzzle her way through tricky situations numerous times before, whether in a game (a context in which “I don’t know” is very rarely followed by “I can’t do it”) or on other math problems.

Furthermore, she could do it. “Doing it” for this assignment was pretty open to interpretation. There was no prescribed method, no real “right answer.” You made a pentagon out of three triangles? Awesome. You made a different pentagon out of two triangles? Well, that’s awesome, too. You now decide to move on to a different shape? Or to stick with two triangles and see what you can do? Or try to make the nicest looking pentagon out of two triangles that you can? There are lots of ways to play with this question and lots of places to have success.

She knew that—partly because I told the class when we started the assignment and partly because that’s how investigations like this always go in in our class. But despite the open-ended nature of the assignment and the wide-reaching opportunities for success and personalization, she was having trouble seeing the possibilities as real…

…Or maybe the open-endedness and wide-reaching possibilities were the problem. Huh. Freedom can be just what some students need to engage with math. But for other students, who maybe hesitate to act ambitiously in math for reasons deeper than feeling stifled or bored by conventional lessons, freedom isn’t enough. They don’t feel confident enough that they will come up with something in this new, open environment, and that the thing they come up with will be valued by others.

In my purely anecdotal and observational experience, the problem of feeling intimidated by freedom in math seems to impact girls more than boys. For many of my male students, being given the opportunity to pose problems, choose their methods, and shape class with their judgments is enough to spark increased engagement. But for a good number of my female students, an environment open to personalization is less welcoming than a more structured environment. And this makes complete sense. In a learning environment with narrow goals, where it’s a matter of procedure to learn how to do something right and easy to know if you have, success is obvious. For students with low confidence, this can be comforting.

And now it’s time for a confession: I never did the “fun” math puzzles when I was in grade school. I did really badly with “enrichment.” My fourth grade math teacher was really “creative,” and I hated it. Opportunities to personalize my math education were around when I was in school, and I turned them down. No thank you. I’ll stick to my procedural, memorization math, which I find exceptionally BORING and POINTLESS— but at least it isn’t scary. I know how to achieve within the structure. If I say, “I don’t know,” in a conventional math environment, my teacher will tell me how to do the problem. And I’ll devote lots of effort remembering it for next time. Success achieved! But if I say, “I don’t know,” in a more creative math environment, my teacher will tell me to… just try something? Use my intuition? I have no faith that either of these approaches will bring me success.

How do we get our less confident (and often female) students to take advantage of opportunities for creativity and personalization in math class?

I don’t have a system. Right now I’m just operating on a case-by-case basis. But here’s what I did with this girl and often do.

My student said to me, “I don’t know… I can’t do this.” I tried asking her where she was stuck and, as expected, she wouldn’t-couldn’t articulate the problem. So I:

1)     Asked her to show me what she had done, and praised it by saying that I’d seen another student do something like it (so she knows that she’s on track with her peers) and that her approach was special in some particular way (so she knows that she has valuable original thoughts).

2)     Using a tone that (hopefully) conveyed that I was curious and didn’t know the answer, gave her a pretty narrow suggestion that was absolutely certain to get her somewhere. Basically, I gave her a solution part of the problem.

Yes, I gave away an answer. I told her how to do something. “Gah!” you (and part of me) may say. “That’s not the point! She’s supposed to figure it out herself!” But, NO, says another part of me. A hallmark of the creative, open-ended approach to math education is that the answer is not the point. It’s the process. If giving her the answer to one part of the problem gives her the confidence to tackle the rest on her own, this is preferable to not giving her an answer and watching her flail around in the dark. And if I’ve designed the problem properly, there will be plenty of room for her to be creative even if I give away a little piece of the game.

Well, it worked. She quickly got a result—and was happy. Then when I gave her a more open-ended prompt (How could you extend this approach? Could you use it on other shapes?), she was able to proceed on her own. She was the first with her hand in the air when I asked her and her classmates to share their findings, and she was clearly proud of her work.

On her way out the door at the end of class, I pulled her aside and reminded her of how class had started for her. She smiled a little and hurried away, clearly not excited to talk about this; but the experience seems to have had an impact. She’s now more likely to ask me questions if she gets stuck, rather than moving straight to despair, and more likely to stick to it even when other people have given up.


This is a much shorter story. The second “I don’t know” came during my Symmetry and Algebra elective for high schoolers. I think what happened stuck out more to me because of what had just happened with my 6th grader in the morning—because I’m pretty sure this happens all the time and I just don’t notice. Especially in this class, which has segregated itself dramatically by gender. (Which I’ll have to write about in more detail later when it’s all over—they’ve been a big struggle.)

Here’s what happened: It was the end of the period. In parting, in the last few minutes, I asked the whole class a pretty new question. It was related to what we’d been talking about, but was new enough that there was no way anyone was going to answer it in the next three minutes. I knew that, they knew that. The idea was to set up something to investigate in the following class.

I ask the question. I pause. I say, “What do you guys think—just instincts, right off the bat?” A little silence. I make eye contact with a girl at the back of the room. She looks a little shifty and says, “I don’t know.”

I make eye contact with a boy a few seats away. He says, “Hmmm…” and launches into a purely speculative, stream-of-conscious-like series of ideas—all of which miss the mark. He knows that they do, and so do the boys sitting next to him—but that doesn’t stop them from chiming in. And why should it? They don’t know, either. But they do know plenty of other things, and they know that a good way to go from not knowing to knowing is to just start putting ideas together. Try things, fail a bit, try more things, fail a little less. They are perfectly comfortable with this.

Meanwhile, the girls in the back sit in dead silence.

As soon as all of this settled in my head, I paused the discussion. I think I said something like, “Guys, please indulge me in a little meta-discussion analysis.” I reminded them that the girl at the back had answered my really open-ended question by saying, “I don’t know.” Then I turned to the boy who had started talking first.

“Lucas,” I asked, “do you know the answer to my question?”

He made a little smirky face. “No! I have no idea.” The boys next to him laughed a little and shook their heads, agreeing.

I shared a little knowing glance with the girls and said something like, “So Lucas doesn’t know, but he’s answering anyway.” And then the bell rang. No time for further reflection. But everyone was laughing a little on the way out—hopefully at themselves as much as at their classmates.

Beauty Is a Math Art Class

5:00 p.m., on a Tuesday afternoon. Halfway through the hour-and-a-half seminar period of high school mathematical art. It smells like Swedish Fish and Sour Patch Kids, and a little musty (but that’s just the smell of the Saint Ann’s School basement). The last song to come over my Bach Pandora Radio station was actually a Bach, but now we’re listening to a little Debussy.

On the floor, near the door, three kids play around on the computer, letting their minds mull over how to turn their fascination with the game Mastermind into a piece of mathematical art. They are inspired by this beautiful image of the game Tic Tac Toe, but they aren’t sure how to implement something like it with such a large game as Mastermind.

To my left, a boy searches the web for a piece of code he needs for his computerized work. He’s so far advanced in computer programming that I have no idea what he’s doing; I just can tell that it’s incredible.

Through the folding wall behind me, I hear a kid on the piano, riffing on some bars of a piece of music written to the square root of two. Now it’s melodic; now jazzy.

A few minutes later, a kid across the room folds something out of paper. “Hey, look at this,” he says. “It looks like a spiral.” The computer programmer beside me looks up, looks thoughtful, and says, “Wow, that’s actually really cool.” He puts his computer aside and scoots over to learn how to make it.

The only disruption to our total state of peace is the occasional scuffle from the duo on the floor at my feet, bickering over where to place the next Sonobe in their polyhedron. The color symmetries just aren’t working out right; it’s hard to build an icosahedron with two colors.

If the kid making a Rube Goldberg machine were here, things would be a bit noisier. The tranquility would be broken by a video of water flowing upwards in spirals or sound waves forcing sand into crazy patterns. He’s thinking that the theme of his machine will be curves, and he wants to incorporate as many as possible—linear, parabolic, sinusoidal, Brachistochrone, exponential… He’s home sick, though.

Me, I just knit. Sometimes I ask a question; sometimes someone asks me something. Am I in charge? I guess so. They’ve had class without me before, though, on a day when I was absent. Usually seminars are cancelled when the teacher is out; but they bought their own Swedish Fish and did their thing.

I love a math class full of bustle and noise, with discoveries, debates, and excitement whizzing around the room. But this is nice, too: a peaceful room where most of the sharing is done by showing, not by telling, and the making of mathematics takes a long time.

The Mathematics of Fairness

We recently played one of my favorite games in my 6th grade class. It’s a fraction game, originally invented by Justin Lanier but altered by me since I’ve started using it. The game is great fun and quite educational—it’s basically war with home-made fraction cards, and I’ll tell you all about how to play it in a future post. This year when we played, though, the most interesting ideas came not from actually playing the game but from trying to make a fair bracket.

In the several years that I’ve played this game with classes of kids, I’ve never had to make the bracket myself. I always have at least one student in the class who plays squash and has way more experience with tournaments and consolation rounds and rankings than I do and is really excited to make a bracket. So, I typically let that kid make the bracket. It’s gone well for the past few years.

But this year, the other kids in the class didn’t want the squash player to be the only one who got to try making a bracket. For better or for worse, I have a class of very competitive kids, and they don’t trust any of their classmates to do anything right. So, as a homework assignment, I asked the kids to design a structure for our tournament. The structure had to be as fair as possible while producing a ranking.

The fair part turned out to be the real challenge. Unfortunately, we had ten different players, both individual kids and pairs playing as a team. Now, ten is very difficult number of players to make into a traditional bracket. During the class discussion leading up to our vote on a tournament structure, I found out that kids dealt with this in various ways. While working on their brackets, they quickly realized that powers of two were best for making brackets. Nothing like designing a bracket for reinforcing the double-ness of a power of two and the lack of double-ness in ten. Lots of byes were going to be necessary. But how many byes? Shouldn’t they be minimized? And how would you determine who gets a bye?

Some kids developed brackets with two byes in the first round and two byes in a middle round. Others had all ten players play in pairs in the first round and worked byes in later. Other kids did way more complicated things. This led to a discussion—is it fairer to have byes in the first round or in later rounds? Which increases the chances that an unworthy deck would get to the final round?

Then there was the question of who gets a bye. Most kids had the byes determined by chance. But a few kids made you “earn” your bye. One girl had byes in middle rounds, with the player who won by the largest amount earning the bye. But in the consolation round, she brought back players who hadn’t lost by very much and let them play again, this time in best of 5 matches to make their second chances “fairer,” to balance the numbers instead. In this way, she emphasized winning in the winners’ tournament and gave second chances in the consolation tournament. This felt most “fair” to her. But does fair mean that everyone has an equal chance of getting a boost or that only those who earn their boost (or were the most unworthily disadvantaged) get one? We talked about this.

Yet another kid decided to abandon a tournament structure altogether. From his perspective, any byes introduced unfairness. No boosts allowed. So, he went for a round-robin, with rankings determined by number of wins and losses. But would a round-robin take so long that its fairness wasn’t worth it? And was the ranking it would produce not quite as ranking-y as the one a tournament would make?

Never had I been in a math class so full of social justice issues. None of the questions we were asking about fairness had correct answers; all are debated frequently in the context of divisive issues ranging from the fairness of the NCAA basketball tournament to affirmative action. I’m considering going back and making these connections to broader social issues more apparent to the kids. Despite being about fairness, though, the work we were doing was still very mathematical.

Eventually, we just voted on it. (Using a first-past-the-post voting mechanism! Not the Coombs method! Or the Borda count! Was it fair??? Aaah fairness!) A narrow plurality chose the round-robin. So, we’re now in the process of playing 90 games of fraction war. Sigh.

(NOTE: It’s actually only 45 games, because I forgot that the board counts each game twice. We took that into consideration on the board, because we crossed out the games mirrored across the diagonal of the grid, but I forgot about that while writing this! Thanks for pointing that out, Sue! It also came up while planning who should play who in each round. That was yet another challenge…)

But, even if the kids get zonked out before finishing the 90 games of fraction war, I feel like the discussions we had were well worth it. We discovered that fairness may depend on context. Equal chances may not be fair; earning your advantage may not be fair either. But sometimes a sacrifice of fairness must be made in the name of accomplishing other goals. Or must it?