fawn mult

 

  1. What exactly is the shortcut?
  2. Why does this shortcut seem reasonable?
  3. We’d all agree, I think, that 2 x 6 = 26 is not a result of this kid not understanding what multiplication is. I’ve made that mistake before, and I bet that you have too. So, why is it a ┬ácommon mistake? What does this say about how a mind works while working on math?

[Any advice on how to tag this, CCSS-wise?]

TheCommonMistake WhatsGoingOnHere

From the submitter: “I came across these answers to sig fig questions when marking a pre-algebra numeracy test last night. I’ve attached two answers, one is a very common mistake where students just can’t believe that they are asked to round up that much. The second… well I don’t have any idea what the student was thinking, so I thought your readers might be able to help.”

Readers?