Are there really no stupid questions?
My student caught up with me at the door of the classroom, just before class was about to begin:
“Dr. Z, I'm really not getting this least common denominator stuff.”
Such last-minute pleas often mean that the student is fishing for some hint or nugget of information that might provide a small advantage on the daily quiz, which is typically the first order of business in my computational math class. I replied in that vein, trying to assuage his fears:
“We're working on multiplication of fractions right now. Common denominators are required for addition and subtraction of fractions, not multiplication. Remember? You'll need to catch up on the common denominator material, but you should be okay for today.”
I had failed to correctly gauge the intent of my student's expressed concern. He proceeded to disabuse me:
“I'm really behind right now, Dr. Z. Do I have to attend class today?”
Oh, that is a really good idea. If you're behind, skip class until you can catch up. That'll work! I maintained just enough presence of mind to give my student the correct answer to his question:
“Of course you do. Now get in there.”
The incident turned out to be a learning experience for my student. He avoided the problem at our next class session by not even showing up.