Decimals Elementary School Measurement & Data Money

Money and Decimals



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!

Elementary School Measurement & Data Subtraction

4 cents short of a dollar

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?