To expand, you can find practice exercises in a textbook. You can track your progress in a textbook. A good textbook is non-judgemental (but God condemn the author who writes “it follows easily that”). Free textbooks are also available online (some better than others).

Sure, Khan’s videos are all sorted and in nice “bite-sized” chunks. But they are mostly sorted by procedure — the organization of the site itself helps inhibit the forming of the mental organization that will help our students. This is reinforced when he doesn’t explain the ideas behind why the procedure works.

I agree that video has its place. A few students have severe cognitive impairments that making reading the textbook completely out of the question. But when I poll my incoming first-year math majors, 98% or so of them have never read an entire section in a single math textbook! Never, and they are mostly planning to become actuaries, math teachers, and mathematicians! The simply CANNOT READ technical content. Sending students to Khan is easy, but does nothing to fix this problem.

I’ll part with this video:
http://www.youtube.com/watch?v=BbX44YSsQ2I&feature=related

I’m surprised at how many people think the guy just doesn’t know how to square and add. Of course he can! The problem is that neither he nor the audience can read.

JUMP Math doesn’t build a case for Gates as embracer of constructivism. There is no way this program could be described as constructivist. For example, take a look at the Grade 3/4 introduction to fractions material: http://jumpmath1.org/sites/default/files/Introductory%20Unit%20Using%20Fractions%20-3%20-%204.pdf

Adding and subtracting fractions is broken down into seven incremental steps to be practiced by students. The first three of these steps are:

1. “Write the times signs beside the fractions” (I’m not making this up)
2. “Switch the bottom numbers” (How’s that for developing understanding?)
3. “Write the times signs and switch the numbers” (Now that you’ve mastered both)

If I were attempting to create a satire of what math education looks like for far too many of our students, I’d be hard-pressed to top what can be found in JUMP. This is not respectful of the mathematical thinking that children are capable of. The approach here is similar to Khan’s video on multiplying and dividing integers: both promote the memorization of rules rather than conceptual understanding.

As Christopher suggested, the video wasn’t pulled because of pedagogy. It was removed because of math errors. With respect to these errors, it might be a bit snarky to nit-pick at things like ‘minus’ instead of ‘negative’. Like many teachers, I catch myself saying things like this from time to time and have to correct myself in class. Thankfully for me, these moments aren’t broadcast on YouTube. Still, I don’t have a problem with snark if one is being held up as the lone stranger riding into town on horseback (or bicycle) to save the townsfolk.

Let’s ignore the criticisms from the constructivists for a moment. Let’s also ignore the nit-pickers. For me, as examples of direct instruction, Khan’s videos just don’t hold up. As John and David pointed out, is there a worse example to start with than -2 times -2? This lack of basic preparation appeals to some who think that it adds charm to the Sal Khan story. To many math teachers like myself, it’s alarming, not charming. If I observed a teacher do the same thing, I’d say s/he should plan more and wing-it less.