What strikes me about this piece of student work is how clean and predictable their mistake is.
Is this sort of mistake the rule or the exception? Does a mistake like this reflect the fact that many/most student errors are due to coherent mental models, or is it the rarer exception in a world dominated by stormy minds that fling ideas at math less predictably?
Thanks again to Dionn!
What’s the mistake? Why is it tempting?
Thanks to Christopher Danielson for this submission. His blog. His twitter.
Let’s have a good old fashioned brawl: is there a mistake here or not?
This submission comes from Chris Hunter, who blogs at Reflections in the Why.
I usually try to at least come up with an idea of what the student was thinking before I post these mistakes on the site. Sometimes, though, I’m totally stumped. Here’s one that got me:
How did the kid get that answer? Anybody?
Also, how would you help the student move forward?
I love this mistake. From their work, what can we infer about what the student knows? Where are they getting confused? How would you help? (Also, if you don’t feel as if you have enough information, feel free to jump in with want information you’d like.)
Elementary teachers? You out there?