Great Classroom Action


Scott Keltner sent a drone up in the sky while his students plotted themselves down below. I emailed Scott and asked for his lesson plan and he sent back something involving playing cards and, frankly, none of it made any sense to me and I seriously don’t understand how the downside of cost, time, and effort could possibly outweigh the upside of drones (!) but I’m so curious. Bug Scott via Twitter to write up what he did here.

Julie Reulbach used zombies to create a need for logarithms. Zombies are, obviously, catnip for some students, but that isn’t what caught my eye here. Julie understood that logarithms are a shortcut for inverting an exponential equation. And if you’d like to create a need for a shortcut it’s helpful for students to experience the longcut, however briefly. Watch her work.

Ollie Lovell used one of my unposted tasks with a group of students in Myanmar who spoke very limited English and whose classroom had no electricity. Imagine how your favorite lessons would have to change under those constraints and then read how Ollie changed his. I learned a lot.

Sarah Hagan shares a game from S T called Greed, which helped turn her students’ perception of box-and-whisker plots from useless to useful. Crucially, the game exploits the need for box-and-whisker plots, which is comparison between multiple sets. Creating a box-and-whisker plot for a single set of data will feel pointless, same as teaching someone to use a carrot peeler by using it to paint a house. That’s not what it’s for!

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. Cultural (and math) sensitivity, from the fruit on a plane lesson:
    1) The collection of fruit doesn’t fit with a -5 to 5 axis, because all of them are likely to be considered tasty. In fact, it is easy to find classrooms in this part of the world where any form of food will get positive marks (b/c food isn’t always available to the kids or their families). Unfortunately, not everyone can afford to be picky about what they eat.

    2) Teaching math in a language the kids don’t understand or speak is really sub-optimal (mathematically). My guess is language difficulty makes this into a traditional lesson experience where the kids try to copy and parrot back what the teacher has done/said.

    This will be missing out all the magic of notice&wonder/3-acts:
    – kids expressing themselves (mathematically)
    – teacher guiding and training for refined expression
    – kids asking their own questions (and seeing that asking questions is a key part of math)
    – kids trying to answer their own questions

    All of that is language based (obviously).

    Sorry to be so critical of someone who is clearly a cool teacher and well-intentioned on his trip.

  2. @joshua

    ah but this isn’t meant to be an all encompassing lesson.
    that’s not the goal at all here, rather it seems to be:

    a) get kids understanding measurement in 2 dimensions with a concept they are all familiar with and which transcends language itself(taste)

    b) get kids comfortable and feeling confident and happy about how such measurement works, in their own way.

    constructive understanding certainly does not follow the 3 acts thing dan purports here all the time, as i’m sure he’d be the first to say.

    as a student of classes in which at least half are learning the classroom language for the first time, points a) and b) are many orders of importance > refinement and language based expression. there are other forms you know, and no matter how talented a student might be mathematically(and i do teach some veritable geniuses), they must first feel comfortable in understanding alternative expressions prior to formulating complex expressions.

  3. mike:

    constructive understanding certainly does not follow the 3 acts thing dan purports here all the time, as i’m sure he’d be the first to say.

    Say what now?