When you ask a question to the class, and someone answers incorrectly, see if you can conversationally edit the question in a way that the student would have been right. That is, respond by starting with, "Well, that would be right if the problem said ____", and fill in the end of that sentence in appropriate way.
I'm very fond of this technique. It actually accomplishes several things:
- Makes things a bit more challenging for the instructor, keeping them on their toes
- Cushions the "no you're wrong" response to the student (a bit like the "shit sandwich" feedback protocol)
- Force you to diagnose & clarify the misdirected mental pathway for you and the student (and in fact usually the student has misperceived some pattern that's just adjacent to the given problem).
Try it and see how it feels. To be clear: I don't do this because I'm bored in class, but nevertheless I've found it to be a compelling and clarifying technique.