...by the people paying attention to me.
A student today was questioning whether a number on the board was a "10" or a "70". The professor told him it was a "10", but the student was being stubborn that it sorta looked like a "70".
So I turned around, and I told him something along the lines of this:
"You see, effective learning requires the combination of both visual and auditory inputs.
"Had you been paying attention to the auditory inputs when the professor originally wrote the number on the board, you would have been aware that it is, in fact, a ten, and this whole misunderstanding would have been avoided."
I believe the professor was quite amused.