I get that there is no perfect lesson. Really I do.

And I get that students leave my classes with wrong ideas. But the thing is, when I come across these wrong ideas, I try to do something about it.

A couple of tweets from the field last week (sender’s tweets are locked, sorry).

S came in today claiming to have used Khan academy last night to learn about decimal place value. Was adamant 0.63 > 0.7 cc @Trianglemancsd

Was also adamant that 0.4 < 0.40. Not feeling overly confident about Mr. Khan and his explaining abilities…

Now, people get fussy when I fault Khan Academy for bad decimal instruction.

If I don’t like the videos, I am told it’s not about the videos; it’s about the exercises.

If I don’t like the exercises, I am told there are new ones in the queue.

If I don’t like the trial versions of the new ones in the queue, I am told that the particular exercises don’t matter; it’s about the knowledge map.

When I say that the knowledge map is flawed, I am told that it doesn’t matter because students can move around in Khan Academy in any way that they like.

And then every day kids are going to Khan Academy for help with decimals. Some of these kids, such as the one in the tweets above, are going there independently. And some of them are going there because *their entire state is piloting it as a primary instructional resource!*

*Whoa there!* they say. *Khan Academy isn’t meant to be a primary instructional resource. *

But then here is a video that Khan Academy produced…

At 20 seconds in, a student teacher in mathematics says this:

When I first [learned] about Khan Academy, it was mostly “my teacher said this, but I can’t remember what he said, so I’m going to go check it out on Khan Academy. So it was more of a personal resource.

That’s kind of where I was thinking it would be in my classroom down the line. “If you’re struggling with this, go check out Khan Academy.”

But now, after coming to this, it

canbe that first step. It can be the go-to. “Hey, go learn this. Go learn the foundations, and then we can take it to the next level in our classroom, and put in those hands-on activities.”

Just to be clear, Khan Academy produced this video. I am not misrepresenting KA here. They are proud to share that a math teacher at a training views Khan Academy as a good primary instructional resource.

Now, I have long been critical of *textbooks* that introduce decimals as though they were a logical extension of the whole number place value system (just ask my students!) I am no fan of what Hung-Hsi Wu calls *Textbook School Mathematics*.

But if you are going to get introduced by the publisher of *The New York Times *[at about 3:00 in the linked video] as “a true pioneer” who is “breaking down barriers” with “heart”, “guts” and “innovation”, I think you have a responsibility at least as great as that of the average textbook author. You have to strive to do better and you have to pay attention to what people already know.

If you are going to repeat that your mission is “a free world-class education for anyone anywhere,” you need to spend some time concentrating on the meaning of *world-class*, rather than imitating the bad textbooks that presently exist.

I have taught many crappy lessons, and I surely have many ahead of me. I do not fault Khan Academy for having a few crappy lessons.

But I seek feedback from my students on what they are learning.

I consult research on learning for the topics they are struggling with. I collaborate with colleagues near and far to improve my lessons.

I do not defend my crappy lessons by calling them unimportant. I own their crappiness.

And I strive to do better next time.

[Comments closed. Hit me on Twitter if you want to talk.]

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