When I was a student teacher (5th grade), my supervising teacher passed out a questionaire to the class where they were to grade the teacher about just about everything. She promised the students she would be unable to read them until the school year was over. She was reading them that afternoon.
My 5th grade teacher was not moved by my question about what numbers were assigned to the years Christ was alive (if BC stands for “Before Christ” and AD meant “After Death” - he muttered something about there being 30 unnumbered years between BC and AD), but he did have the good grace to be convinced when I showed him what the dictionary said about AD.