A Critical Language for Problem Design

I am at the Joint Mathematics Meetings this week. I had a conversation yesterday, with Cody L. Patterson, Yvonne Lai, and Aaron Hill, that was very exciting to me. Cody was proposing the development of what he called a “critical language of task design.”

This is an awesome idea.

But first, what does he mean?

He means giving (frankly, catchy) names to important attributes, types, and design principles, of mathematical tasks. I can best elucidate by example. Here are two words that Cody has coined in this connection, along with his definitions and illustrative examples.

Jamming – transitive verb. Posing a mathematical task in which the underlying concepts are essential, but the procedure cannot be used (e.g., due to insufficient information).

Example: you are teaching calculus. Your students have gotten good at differentiating polynomials using the power rule, but you have a sinking suspicion they have forgotten what the derivative is even really about. You give them a table like this

x f(x)
4 16
4.01 16.240901
4.1 18.491

and then ask for a reasonable estimate of f'(4). You are jamming the power rule because you’re giving them a problem that aims at the concept underlying the derivative and that cannot be solved with the power rule.

Thwarting – transitive verb. Posing a mathematical task in which mindless execution of the procedure is possible but likely to lead to a wrong answer.

Example: you are teaching area of simple plane figures. Your students have gotten good at area of parallelogram = base * height but you feel like they’re just going through the motions. You give them this parallelogram:
Of course they all try to find the area by 9\times 41. You are thwarting the thoughtless use of base * height because it gets the wrong answer in this case.

Why am I so into this? These are just two words, naming things that all teachers have probably done in some form or another without their ever having been named. They describe only a very tiny fraction of good tasks. What’s the big deal?

It’s that these words are a tiny beginning. We’re talking about a whole language of task design. I’m imagining having a conversation with a fellow educator, and having access to hundreds of different pedagogically powerful ideas like these, neatly packaged in catchy usable words. “I see you’re thwarting the quadratic formula pretty hard here, so I’m wondering if you want to balance it out with some splitting / smooshing / etc.” (I have no idea what those would mean but you get the idea.)

I have no doubt that a thoughtful, extensive and shared vocabulary of this kind would elevate our profession. It would be a concrete vehicle for the transmission and development of our shared expertise in designing mathematical experiences.

This notion has some antecedents.[1] First, there are the passes at articulating what makes a problem pedagogically valuable. On the math blogosphere, see discussions by Avery Pickford, Breedeen Murray, and Michael Pershan. (Edit 1/21: I knew Dan had one of these too.) I also would like to believe that there is a well-developed discussion on this topic in academic print journals, although I am unaware of it. (A google search turned up this methodologically odd but interesting-seeming article about biomed students. Is it the tip of the iceberg? Is anyone reading this acquainted with the relevant literature?)

Also, I know a few other actual words that fit into the category “specialized vocabulary to discuss math tasks and problems.” I forget where I first ran into the word problematic in this context – possibly in the work of Cathy Twomey-Fosnot and Math in the City – but that’s a great word. It means that the problem feels authentic and vital; the opposite of contrived. I also forget where I first heard the word grabby (synonymous with Pershan’s hooky, and not far from how Dan uses perplexing) to describe a math problem – maybe from the lips of Justin Lanier? But, once you know it it’s pretty indispensible. Jo Boaler, by way of Dan Meyer, has given us the equally indispensable pseudocontext. So, the ball is already rolling.

When Cody shared his ideas, Yvonne and I speculated that the folks responsible for the PCMI problem setsBowen Kerins and Darryl Yong, and their friends at the EDC – have some sort of internal shared vocabulary of problem design, since they are masters. They were giving a talk today, so I went, and asked this question. It wasn’t really the setting to get into it, but superficially it sounded like yes. For starters, the PCMI’s problem sets (if you are not familiar with them, click through the link above – you will not be sorry) all contain problems labeled important, neat and tough. “Important” means accessible, and also at the center of connections to many other problems. Darryl talked about the importance of making sure the “important” problems have a “low threshold, high ceiling” (a phrase I know I’ve heard before – anyone know where that comes from?). He said that Bowen talks about “arcs,” roughly meaning, mathematical themes that run through the problem sets, but I wanted to hear much more about that. Bowen, are you reading this? What else can you tell us?

Most of these words share with Cody’s coinages the quality of being catchy / natural-language-feeling. They are not jargony. In other words, they are inclusive rather than exclusive.[2] It is possible for me to imagine that they could become a shared vocabulary of our whole profession.

So now what I really want to ultimately happen is for a whole bunch of people (Cody, Yvonne, Bowen, you, me…) to put in some serious work and to write a book called A Critical Language for Mathematical Problem Design, that catalogues, organizes and elucidates a large and supple vocabulary to describe the design of mathematical problems and tasks. To get this out of the completely-idle-fantasy stage, can we do a little brainstorming in the comments? Let’s get a proof of concept going. What other concepts for thinking about task design can you describe and (jargonlessly) name?

I’m casting the net wide here. Cody’s “jamming” and “thwarting” are verbs describing ways that problems can interrupt the rote application of methods. “Problematic” and “grabby” are ways of describing desirable features of problems, while “pseudocontext” is a way to describe negative features. Bowen and Darryl’s “important/neat/tough” are ways to conceptualize a problem’s role in a whole problem set / course of instruction. I’m looking for any word that you could use, in any way, when discussing the design of math tasks. Got anything for me?

[1]In fairness, for all I know, somebody has written a book entitled A Critical Language for Mathematical Task Design. I doubt it, but just in case, feel free to get me a copy for my birthday.

[2]I am taking a perhaps-undeserved dig here at a number of in-many-ways-wonderful curriculum and instructional design initiatives that have a lot of rich and deep thought about pedagogy behind them but have really jargony names, such as Understanding by Design and Cognitively Guided Instruction. (To prove that an instructional design paradigm does not have to be jargony, consider Three-Acts.) I feel a bit ungenerous with this criticism, but I can’t completely shake the feeling that jargony names are a kind of exclusion: if you really wanted everybody to use your ideas, you would have given them a name you could imagine everybody saying.


Sh*t I F*cking Love (Wherein I Am Moved to Profanity by Enthusiasm)

Shawn Cornally doing his thing.

My new favorite blog, chronicling an adventure in striving to keep math class true to your deepest commitments. (Thanks to Work in Pencil for the recommendation.)

Paul Salomon’s “imbalance problems”. You know how I love a thought-provoking picture.

Math Munch. If you haven’t yet checked out this joint project of Paul, Anna and Justin yet, you should get on that.

Some Followup on “A Note to My Fellow White People”

If you were interested, challenged or otherwise engaged by my Note to My Fellow White People, I have come across a bunch of other things recently you will be interested in:

Here is the other video he refers to in the video:

Also a propos is this recent opinion piece in the NYT by Ta-Nehisi Coates.

I was talking in general about white people receiving feedback about race, but several people who commented took it (very reasonably) in the direction of how to have conversations about race in the classroom. In which case I have the following strong book recommendation:

High Schools, Race, and America’s Future: What Students Can Teach Us About Morality, Community, and Diversity

I am cross-posting my review of this book on goodreads.com:

Full disclosure: the author of the book is my dad. The high school featured in the book is the one I both attended and taught at.


This is a beautiful book. The author is a (white, Jewish) professor of philosophy at a university. The book chronicles his venture into teaching a class about race and racism at his local racially diverse public high school. It offers a model of what a functioning, productive cross-race conversation about race and racism can look like, in an era where (depressingly) this is still a rarity. It makes a case for the civic value of integrated public education in an era where we seem to be forgetting that education even has a civic purpose.

It belongs broadly to the genre of teaching memoirs, along with books like Holler if You Hear Me. But two related features distinguish it in this genre:

(1) The author is a serious scholar. Unsurprisingly, then, the content of the course he taught features heavily in the book. So this teaching memoir also functions, with no cost to readability, as a scholarly book about race. (As an aside, I am very proud of him on the readability front. It was a real stretch for him to write a book whose style didn’t place a technical burden on the reader, and it took a lot of rewrites, and help from his editor, but he totally pulled it off!)

(2) The genre is characterized by taking students seriously as moral and psychological beings. That’s one of its strengths as a genre as a whole. But this is the first book I’ve read that takes students equally seriously as intellects. The author often writes with plain admiration for his students’ ideas. This may be my favorite feature of all. Developing students as minds is, after all, the point of education. So it strikes me as surprising that it’s so rare for a memoir about the lived experience of teaching to give such loving attention to what those minds produce.

Some Miscellaneous Awesomeness

Just some awesome stuff I feel like pointing out:

Vi Hart does it again. That young woman has created a new art form.

Terry Tao’s airport puzzle. If you have to get from one end of the airport to the other to catch a plane, but you really need to stop for a minute to tie your shoe, is it best to do it while you’re on the moving walkway or not? (I learned this problem from Tim Gowers’ blog.)

Paul Salomon quotes Vi Hart quoting Edmund Snow Carpenter, and the quote is absolutely worth me quoting yet again:

The trouble with knowing what to say and saying it clearly and fully, is that clear speaking is generally obsolete thinking. Clear statement is like an art object: it is the afterlife of the process which called it into being.

Dan Goldner is doing my job for me. The original purpose of this blog was to read writing about math education, and to summarize and discuss it. I don’t do this very much any more (although expect summaries of a couple articles from the current JRME in the next few weeks months), but I do have a long list of things I wanted to read and discuss here but figured I’d probably never get to. On this list was the 1938 NCTM Yearbook, The Nature of Proof, by Harold Fawcett. But I’m taking it off; Dan’s got it covered.

Another One to Keep Your Eye On: Anna Weltman

Here’s another blog to keep an eye on:

Recipes for Pi, by Anna Weltman.

I know Anna IRL. In fact, both of us have seen the other one teach. Thus prior to discovering her blog I already knew her as mathematically thought-provoking, endlessly creative, and deeply tuned in to student experience, not to mention a total sweetheart.

So I was excited to learn that she had started blogging in February, and her writing hasn’t disappointed. It’s sporadic, but who am I to complain about that, and more importantly it’s characterized by that same deep thinking about math and student experience that marks her teaching. Check it out.

Aside: Anna teaches at St. Ann’s School, along with Justin Lanier, Paul Salomon, and Paul Lockhart.

Never Be Wobbly

I spent at least 9 hours today thinking about squishing baloon-shaped surfaces into other shapes. This is what a PhD program in math is doing to me.[1]

Having learning as a full-time job is really, really delicious. But tonight when I stopped mathing and engaged the edublogosphere it felt like a relief to read about classrooms, populated by humans. (To my fellow humans: I love the differentiable manifolds but I love you more.) Thanks Jesse Johnson, Dan Goldner, and Kate No Wackness[2] for your continuing dedication to learning (your kids’, yours and ours).

Holy Crap, a Three-Legged Table Can Never Be Wobbly.

This is my favorite thing ever.

[1]The particular thought that was driving me crazy at least from 7pm to 10pm, not that you care, was: if f:X \rightarrow Y is any surjective continuous function between topological spaces that maps open sets to open sets, then I can prove that the inverse image of a compact set is compact. I studied a converse if X and Y happen to be smooth manifolds and f happens to be an injective immersion. But these are very very strong assumptions. How much can they be weakened?

[2]Kate, this is A’s name for you. (An homage to your no bullsh*t approach.)

Dan Goldner

This is a shout out.

Dan Goldner came on my screen last summer during Riley’s soft skills conference. My impression was that he was a bright-eyed bushy-tailed newbie (just off the student teaching year) with a surprising amount of classroom insight considering this.

At the end of the summer I met him IRL in a miscellaneously awesome context and have been following his blog Work in Pencil since then. In the fall of his first full-time year in the classroom, he didn’t produce a lot of content. (No surprise.) 2 posts in the early fall, 2 right before Christmas, then nothing for months. (I guess I’m not one to talk.)

But now he’s back, and I feel that my initial impression last summer, while quite positive, was actually an underestimate. I didn’t anticipate all this maturity. I want to let you read for yourself, so I’m going to minimize the endorsement verbiage. I will say this: disconcerting forthrightness and vulnerability combined with some real writing craft. Keep your eye on this one.

These two are my favorites. Go read now.

The Math Wizard

Okay, one more shout out.

My colleague Japheth Wood (News from the Math Wizard), with whom I’m delighted to be co-teaching a class for preservice teachers, is an awesome problem composer. He’s also been dipping into the sea of math and math ed blogging, one toe at a time. He’s finally got one whole foot in:

Check it.

In particular, check out that image.

Don’t move past it to the text (mine or Japheth’s) until you’ve sat with it long enough to absorb everything. If you find yourself with a mathematical question, don’t move on till you’ve tried to answer it.

Seriously; stop reading and go look.

There’s a lot of difference, pedagogically and content-wise, between this image and Dan’s boat-in-the-river video but there’s something very important and very exciting in common. Both manage to ask a very specific and mathematically rich question without whispering a single word. I think the natural current could be strengthened a bit by putting little venus flytraps on top of the square numbers, but that’s the only improvement I can think of.

So, questions for you:

a) What question, if any, does that image leave you with? (Am I right that there is a natural question you can’t help but have once you’ve absorbed the image?)
b) What are the features of the image that lead to the question? Given a mathematical question, how do we go about turning it into a wordless image that asks it?

FOLLOWUP (10/1/10):

Japheth and I passed out slips of paper to our class of preservice math teachers a week ago. On the slips were either Japheth’s original image, or tieandjeans’ modification. We asked them to write down a mathematical question that the paper provoked, and then try to answer it. We didn’t give them a ton of time. (Less than 10 min.) Interestingly, while I thought the sense of danger in the modification would make the gravitational pull toward our intended question (will the grasshopper manage to avoid all the squares?) greater, our students’ knowledge of Super Mario Bros was a distraction, because the up/down motion of the plants, and the question of Mario’s specific trajectory, became relevant considerations. (You can see below that one group, perhaps reading what we were going for, explicitly ruled out those considerations.) So I think the students that got the original grasshopper image actually gravitated toward the intended question more predictably. I still think the sense of danger would help, but maybe we just keep the grasshopper and add venus flytraps that appear static and aren’t close to the trajectory?

Anyway, here’s what they came up with. As you can see, for all of the above, the natural current is still pretty strong.

Grasshopper / Mario Problems


If the placement of fly traps continues, and Mario times his jumps so the trajectory never hits the plant, will he ever land on a fly trap and die?

a^2 = 4n + 2. No.


Does Jiminy land on a box?

4k+2, k\in\{0,1,2,\ldots\}
k^2 = 4k+2
k^2 - 4k - 2=0 —> k = 2 \pm 2\sqrt{6}


When does Mario’s jump not clear the venus fly trap?


Will the grasshopper land on one of the empty boxes (perfect squares)?


Hopping by 4. What is the mathematical formula to determine where Mario lands?

Mario will never land on a perfect square.


How many times will the grasshopper land between consecutive perfect squares?

For # between (n-1)^2, n^2, if odd then (n-1)/2, if even then n/2.

Will he ever land on a perfect square?


Can the grasshopper keep jumping without hitting the black box? If no, then when will he hit the black box?


Grey boxes increase by +4
Black boxes increase by consecutive odd #s, +3, +5, +7, +9

Do you notice a pattern between the grey boxes? How about the black? Can you predict what # Mario will land on next?

The next plant will appear at 36. Mario will land at 26, then 30.

When will Mario land on a flower (perfect square)?


2+4y = n^2

Will Mario die and when?


When will Mario land on a plant?

Can he change the size of his jumps and still ensure he will not land on a plant?


Will the grasshopper ever land on a black square?

Can (4n-2) be a perfect square?


Will the grasshopper land on a boxed number (i.e. a perfect square)?

4n - 2 = (y^2 + 0^2)
Sum of squares must be a multiple of 4 or odd.

(Ed. note: they’re misquoting a result they found the previous week. The result was about the difference of squares.)