Dan Meyer

Total 1628 Posts
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.

Great Classroom Action

Bowman Dickson’s students discover the power rule:

This was laborious and took a ton of time in class, but by the end I felt like students really understood well the idea of a derivative. More importantly, were itching for an easier way to find it. They had all these great ideas that they were proposing, so it was easy to funnel their energy into the next phase.

Sarah (@mathequalslove) on random square root review:

Ten minutes before class was about to start, I had an epiphany. What if I made the number under the radical sign random and unpredictable?

Nico Rowinsky on the abstraction we call “a histogram”:

For the most part, as a class, we tried to organize, sort, structure, and then label our way into a graphical representation. The end product was a histogram of travel time intervals versus frequency. However, during one of my classes, I tried something a little different.

Ian Byrd writes up the best modeling task I’ve seen in months:

A practical application of multiplication is to quickly count large numbers of objects arranged in a pattern. And where do we see large numbers of objects arranged in an array? How about parking lots? As a Californian, the parking lot that stands out to me is Disneyland’s enormous “Mickey and Friends” structure.

Better Online Math

tl;dr version

Currently, online math websites comprise video lectures and machine-scored exercises.

For several different reasons, online math websites should add an introductory challenge that activates a student’s intuition and intellectual need. The video lecture should then be directed at satisfying that particular intellectual need.

Here’s an example. Let’s make this happen.

tl version

Online math sites are quickly defining math down to a) watching lecture videos and b) completing machine-scored exercises. I’m not going to re-litigate whether or not that definition of mathematics is as good as what we find in the best classrooms in the highest-performing countries. (It isn’t.) Instead, I’m going to take this online model for granted and ask how we can make it better.

What should we improve? It isn’t the lectures.

For some time there, I was meeting with founders who were pitching their startups as “Khan Academy plus [x]” where x was anything from better graphics, better lesson scripting, a face on the screen, or multiple choice questions embedded in the video. (Here’s basically the entire set of [x] at once.) I don’t believe there’s much value to add there. The Mathalicious lecture videos are beautifully shot. TED-Ed pairs their lecturers with world-class animators. Woodie Flowers wants to see Katy Perry and Morgan Freeman narrate these videos (I think he’s at least half serious) and my suspicion is that we have reached a point of diminishing returns on the efficacy of lecture videos. Once we passed a certain point of coherence and clarity, watching Drake rap over a combinatorics lecture animated by the Pixar team just isn’t adding a helluva lot. If math were only about clear and coherent lectures, we could probably close up shop here in 2012. Thankfully, there’s more interesting work to be done.

So what should we improve? It probably isn’t the exercises either.

The machine learning crowd seems very impressed by the millions of rows in their databases which represent the clickstream of hundreds of thousands of users. That clickstream can tell a teacher how many hints the learner requested, how long she spent on a given problem, whether she’s more apt to score well on machine-scored exercises in the morning or evening. But what the learner and her teacher would really like to know is what don’t I understand here? And machine learning has added very little to our understanding of that question. So there’s certainly value to be added there but I’m pessimistic that machines are in any position right now to evaluate a written mathematical assessment at anywhere near the skill of a trained human.

So what should we improve? We should improve what happens before the lecture.

Currently, the online math experience begins with a lecture. The implicit assumption is that students need to be talked at for awhile before they can do anything meaningful. Not only is that untrue but it results in bored learners and poor learning.

Dan Schwartz, a cognitive psychologist at Stanford University, prefaced student lectures with a particular challenge [pdf]. He asked students to do something (to select the best pitching machine from these four) not just to watch someone else do something. Those students then received a lecture explaining and formalizing what they had just done. Those students scored higher on a posttest than students who were pushed straight into the lecture without the introductory challenge.

I’ll show you an example of how this could work online. Head to this website and play through.

Let me explain what I’m trying to do there. First, any student who knows or can intuit the definition of “midpoint” can attempt that opening activity. It’s an extremely low bar to clear. The lesson will ultimately be about the midpoint formula but we haven’t bothered the student with a coordinate plane, grid lines, coordinate pairs, or auxiliary lines yet. Save it. Keep this low-key for a moment.

Once the student guesses, she sees how her classmates guessed, which queues everyone to wonder, “Who guessed closest?”

We’ve provoked the student’s intellectual need and set her up with the kind of introductory challenge that prepares her for a future lecture.

So we move into the lecture video, which has several goals:

  1. It references the introductory challenge explicitly. The point of the lecture is to bring some resolution to the conflict we posed in the introduction: “Who guessed closest?”
  2. It offers a conceptual explanation of the midpoint formula, not just a recitation of procedures.
  3. It explains very explicitly why we use abstractions like x-y pairs and a coordinate plane. This satisfies John Mason’s recommendation that we become much more explicit about the process of abstraction.

After the lecture, the student sees the original problem, now with x-y pairs and a coordinate plane. No longer does she simply guess, aim, and click. She calculates. There’s are blanks for the answer now. We have formalized the informal.

The student calculates the answer and finds out how close she was. We should also throw some love on the closest guesser who may be a student who doesn’t usually get a lot of love in math class.

After that resolution, we ask students to practice their skills, but not just on automatically generated clones of the same problem template. We give them the midpoint and ask them to work backwards to one of the original points. That’s essential if you want me to have confidence in your assessment of my student as a “master” of the midpoint formula.

That’s it. An intuitive challenge that precedes a lecture video that explains how to resolve the challenge. That’ll result in more engaged learners and better learning.

Other examples?

And on and on and on. There isn’t a recipe for these challenge but I know two things about all of them:

  1. Math teachers have a stronger knack for creating these challenges than people who haven’t spent years fielding the question, “Why am I learning this?” fourteen times a day.
  2. These challenges are more fun when they’re social. It’s one thing to see my own guess at the midpoint. It’s another thing entirely to see all my classmate’s guesses next to mine. We need the Internet to facilitate that quick, cool social interaction. It just isn’t possible with bricks and mortar alone.

Current online math websites have managed to scale up the aspects of decades-old math learning that few of us remember fondly. We can tinker around the edges of those lectures and exercises, adding a constructed response item here or a Morgan Freeman narration track there. Or we can try something transformative, something that draws from the best of math education research, something that takes advantage of the Internet, and makes math social.

BTW:

  1. I made that site for my final project in Patrick Young’s summer Front-end Programming course at Stanford, which, as I mentioned previously, was a pile of fun. If I can make that site in a couple weeks with a thimbleful of programming knowledge, I’m eager to find out what your team can do with its acres of talent and piles of VC funding or non-profit donations.
  2. This isn’t real-world math. I thought initially to pull in some tiles from Google Maps and set up a scenario where the student had to place a helicopter pad exactly between two cities. I don’t think it matters. Students ask “Why am I learning this?” because they feel stupid and small, not because they want you to force a context onto the mathematics. I’m trying to demonstrate that here. Everyone can click on a guess. No one feels stupid and small. Any context would be beside the point.
  3. Cost-benefit analysis. Too often we apply a benefit-benefit analysis to edtech. But there are clear costs to the model I’m suggesting here even apart from the cost of the technology itself. There were at least five different moments over that five-minute lecture where I wanted to stop, pose a question, or have students work for awhile. We lose that here. I acknowledge those costs. We may still come out ahead on benefits if we can scale this up cheaply. “Pretty good” times millions of students may outweigh “great” times thirty.

2012 Nov 7.

A couple of useful tweets.

I’m concerned the competitive vibe appeals only to males, but FWIW this is exactly the kind of reaction I’m trying to provoke.

It isn’t! It’s passively discouraged, which is a huge bummer. I can think of at least two ways a student might think about the midpoint and how to find it. You can take half a side of the right triangle and add it to the point with the smallest value or you can subtract that half from the point with the largest value. Those multiple methods and the discussion about their equivalence are to be prized and they’re lost in the video lecture format. They’re lost. That’s absolutely a cost and not a small one.

2012 Nov 12. Mr. Samson reminds me of the Eyeballing Game, which has been nothing if not an enormous inspiration for the work I’m doing here.

2012 Dec 7. David Lippman does this discussion a favor and creates an environment where the video pauses for student input. Discuss.

Featured Comment

Michael Serra, author of Discovering Geometry:

Curiosity and engagement will always trump “real world” applications. Games, puzzles, being surprised or caught off guard with something new and trying to find out why, these are big tools in our teacher toolbox.

Computers Are Not A Natural Medium For Doing Mathematics

Exhibit A:

The simplest thing, “Take a picture of one of the proofs you just wrote and email it to me.” turns into twenty minutes of troubleshooting cameras that don’t work, and picture files we can’t find in order to attach them, and how to login to your school email account.

This isn’t an exhibit of doing mathematics or of technology enabling a classroom. This is an exhibit of an entire classroom spending time and administrative capital accommodating the limitations of computers, of technology disabling a classroom.

The tools need to get out of the way. When I use the Internet to communicate these words across time and space, I’m not consciously aware of all the technologies that facilitate that communication. They are out of my way. Computers are a natural medium for communicating words. In Kate Nowak’s class, the tools are consciously in the way.

Featured Comments

Dave Major:

Over the past couple of months I’ve heard “yeah, that’s cool, but I can do the same using x, combined with y and converted using z, backing onto Dropbox” far too many times.

Paul Topping:

With plain text, we go to a computer first to type it. Many of us have noted how he hardly ever handwrite anything longer than a phone number or address these days. The same can’t be said for math notation. Some can write math using LaTeX but that is far from ideal. Even mathematicians who are LaTeX experts do not handwrite it on paper or a whiteboard. They use standard math notation.

[3ACTS] Pixel Pattern

You’ve heard of pile patterns? There are variations but generally you have three snapshots of a growing shape like this:

Questions follow regarding future piles, past piles, and a general form for any pile.

I wanted to know what this old classic would sound like with newer equipment. Would video add anything here, for instance? Here is the result of my tinkering:

Video adds the passage of time. I added a red bounding box to the video, which was an attempt to make the question, “Where will the pattern break through the box, and when?” perplexing to students.

I also added different colors, which allows students to track different things or ask themselves, “What color will be the first color to break through the box?” Different questions require different abstractions. If you care about total tiles, you’ll model the total. If you care about the breakout, you’ll model the width and height. Each one will require linear equations, which is nice.

Other notes:

  • The sequel asks about the “aspect ratio” of the growing shape which is a useful way to dig a little at limits.
  • Real-world math. Here again I’m thumbing my nose at our conviction that math should be real. This isn’t real in the sense we usually mean. If it interests your students, it will interest them because it asks questions that rarely get asked in a math classroom, questions from the bottom of the ladder of abstraction:
    • What questions do you have?
    • What’s your guess?
    • What would a wrong answer look like?
    • What information do you need to know?

The Smarter, Balanced Sample Items

The Smarter, Balanced Assessment Consortium:

Five swimmers compete in the 50-meter race. The finish time for each swimmer is shown in the video. Explain how the results of the race would change if the race used a clock that rounded to the nearest tenth.

You should take a tour through the Smarter, Balanced Assessment Consortium’s released items, make an opinion about them, and share it here. California is a member state of SBAC, one of two consortia charged with assessing the Common Core State Standards, so I’m comparing these against our current assessments. Without getting into how these assessments should be used (eg. for merit pay, teacher evaluation, etc.) they compare extremely favorably to California’s current assessment portfolio. If assessment drives instruction, these assessments should drive California’s math instruction in a positive direction.

The assessment item above uses an animation to drive down its word count and language demand. It’s followed by an expansive text field where students are asked to explain their reasoning. That stands up very well next to California’s comparable grade five assessment [pdf]:

  • Elsewhere, we find number sense prized alongside calculation (here also) which is a step in a very positive direction. (ie. Our students should know that $14.37 split between three people is between $4 and $5 but it’s a waste of our time to teach that division longhand.)
  • I’ve been assuming the assessment consortia would run roughshod over the CCSS modeling practice but on the very limited evidence of the sample items, we’re in good shape.
  • The assessments do a lot of interesting and useful things with technology. (Reducing word count, at the very least.) I only found one instance where the technology seemed to get in the way of a student’s expression of her mathematical understanding.

I can’t really make an apples-to-apples comparison between these items and California’s current assessments because California currently has nothing like this. No constructed responses. No free responses. No explanation. It’s like comparing apples to an apple-flavored Home Run pie.

Featured Comment:

Candice Frontiera:

Next thing to explore: Technology Enhanced Item Supporting Materials [zip]. [The “Movie Files” folder is extremely interesting. –dm]