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.

How did this happen? How might you help?

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?

What’s the mistake, and how would you move this student forward to a complete understanding of how to solve inequalities?

What is this student thinking? It’s a bit tricky, so extra points if you come up with a complete story that includes a list of things that we know that this kid knows.

What aspect of solving linear equations is this student struggling with?  From the student’s point of view, why does the moves made seem like the right ones?

Are there any interesting things that you do to help students with linear equations? How do you make the right moves seem intuitive?