What does this question reveal about the student’s understanding?
(Also: do you agree with the mark given by the teacher?)
Categories
Category: Algebra 1
Comment on anything, but note the parentheses.
Categories
1 – (-1)
Three points to you if you can convincingly explain where “x = 2” comes from.
Why do kids make this mistake?
What’s up? How do you help kids avoid this mistake?
Thanks again to Andy Zsiga for the submission.
Categories
Impossible Graphs
How would you mark these problems? What do the kids understand? What don’t they?
What would the kid put as answers to the question on the right? Explain your choice in the comments.
Many thanks to Andy Zsiga for the submission.
Clearly the kid doesn’t have a deep conceptual understanding of how to solve equations or simplify expressions. True, the kid probably learned some stuff proceduraly as opposed to conceptually. (Though, I can confirm, that in this classroom nobody ever said anything, like, “When you have an equation you need to add something to each side to isolate the x.” The balanced-scale model was used at first.)
There’s still two interesting, deeper questions, to consider. (Possibly more: bring it up in the comments.)
a) Would this kiddo always make this mistake, when presented with an expression to simplify?
b) If not, then what exactly is it about this problem that prompts the kid to employ a basic move from equations?
