The student clearly needs more practice with solving equations. Fine. But why did the student make this mistake, in particular? After all, there are dozens of ways to mess up this problem. Why was this way tempting?
Today’s submissions comes Louise Wilson, who blogs over at Crazed Mummy.
What’s the mistake? Diagnose the disease, and find the cure in the comments.
Thanks to Anna Blintsein for the submissions. Go follow her on twitter!
How would you help this student become sensitive to this language?
Another quality submission from John Weisenfeld.
How did this happen? How might you help?
Here are two classic mistakes:
Whenever I see a mistake that recurs at all different levels, and with all different students, I wonder: what makes this mistake so attractive? What’s the misconception? And what can we do about it?
Say something smart in the comments, and then go check out this post from Fawn Nguyen.
What’s the mistake? Where’d it come from? How would you help?
When you’re done thinking about that, go check out where the mistake came from.
Where did the kid get 48 from? How would you help him, err, not get 48 in the future?
Clearly, the student’s work has more than one issue. But what issues doesn’t it have? What does the student clearly know that you could build on? What’s something that he clearly needs to work on, and how would you help?
In case you’re having trouble reading the kid’s work, and because the top of the question is cut off, I’m going to reproduce the problem in text below the image:
Question: What is the product of 
Answer:
The usual: What does he know, what doesn’t he know, and what would you do next?
What’s the mistake, and how would you move this student forward to a complete understanding of how to solve inequalities?
