Taght that lesson. I liked it. Love that book series. Great questions, easy to differentiate.

To clarify, the question about the swimming pool is a genuine one, and gets to a larger question I continue to have about what makes a context “pseudo.” In an earlier post, you defined a pseudo-contextual task as one in which:

1. The task asks a different question than the one most people would naturally ask, and/or
2. The task prompts students to use math that they wouldn’t otherwise use.

Using these criteria, the pool task is certainly more authentic than is, say, the robot example. How many tiles? is the question I’d ask, and an algebraic expression is the tool I’d use to answer it. Meanwhile, there isn’t anything in the robot description that screams “rational functions” to me.

That said, these criteria don’t seem sufficient to me, or rather, they seem to jump the gun. When we label the robot task as a “pseudo-context,” what we’re really critiquing is how the authors use the context. But Mega-Grandma? It’s a thing. Minimizing manufacturing costs? That’s a problem. The developers may have asked bad questions, but the situation itself is legit.

Contrast this with the pool problem. If the robot problem is an example of “bad questions about a real situation,” the pool problem seems to me like an example of “good questions about an invented situation.” I say that for two reasons. First, I can’t recall ever having seen a square swimming pool. Second, even if what we’re talking about is a hot tub, I have a hard time imagining that technicians use (4n – 4) to calculate how many tiles to buy. Instead, I imagine that they buy tiles in bulk and, if the tiles don’t fit the perimeter perfectly, that they use grout.

I don’t think this means the the pool task is bad. On the contrary, I think it’s a wonderful activity for helping students understand how to write algebraic expressions. Still, given that “pseudo” literally means “not genuine,” I have a hard time seeing any fundamental difference in authenticity between the robot task and the pool one. They both involve invention, just at different steps in the process: one given the context, and the other to get the context.

Which brings me back to my question about the two criteria above. My own preference for authentic applications notwithstanding, I think you make a valuable point about the dangers of treating “real world” as a magic bullet, and I agree that many math tasks are so forced as to be laughable. At the same time, I notice that most of the tasks you’ve developed recently are grounded in some ostensibly real-world situation, whether a taco cart or pennies or a pool. If we take a context as given, your two criteria make sense to me. Yet before we ask whether a certain context prompts students to naturally answer the natural question, is it important to first ask whether the context itself is a genuine one? Before 1 and 2 above, should there be some Criteria 0: If the situation is grounded in a real-world context, does that context actually exist in the form it’s presented?

I’ve been trying to come up with a clean way to distinguish between conceptual understanding tasks and applications for a while. It’s proven trickier than I expected — more of a gradient, perhaps, than a line — but the question of where a task comes from keeps popping up: namely, was the motivation to use math to explain something in the external world, or was is to illustrate some underlying mathematical concept (and a “real world” context simply provided helpful grounding). Somewhere in there, I suspect my question about the pool is related to this.

I’m interested in your observation that if you ditched the pool context, most kids would still dig the lesson. I expect you’re right; it reminds me of the snake pattern video from Sadie’s classroom. In that case, if what you’re after is the “puzzling,” and if the animated pattern sparks that already, why use the pool context at all? Perhaps the tiles lingo makes it easier for kids to talk about, but are you concerned at all that the pool frame (1) risks clouding the appreciation of math for its own sake, and/or (2) risks setting kids up to say, “But this isn’t how pools are actually designed?”

I’d love to know more about how you balance those two ideas — concreteness and abstraction — and how you decide whether a context will facilitate the process vs. get in the way.

Totally agree, BTW, with your added criteria. I’m actually re-going through our library now, and am seeing some examples where we leaned way too hard on the context. An excellent, excellent point.