I'm surprised by the tone of the comments so far. In the article I see a clear parallel between the example teacher doing things right, and the hacker mentality

I'm surprised by the tone of the comments so far. In the article I see a clear parallel between the example teacher doing things right, and the hacker mentality. Think of it as an overall problem with code - how do you teach someone how to get good at debugging? A more generic version of that question may be simpler, but maybe even harder to answer: how do you teach general problem solving skills? The teacher in the article was doing nothing less than debugging erroneous logic as applied by her students. Not just for the procedural errors, but for the underlying faults which allowed the logical errors to manifest. That's pretty hard core.