This allows changing the display, but if you operate it accidentally, you may be unable to read the display. But your calculator may express it as 1.00 - 4, which may at first appear to be a mistake. A proper use of the MODE feature can prevent this accident, but some calculators are not so quick to switch to scientific notation. The purpose of this class is learning in a pleasant, intellectual environment. Students should feel comfortable thinking about the subject matter and asking questions.
Some questions are to clarify statements made by the instructor.
Other questions are to explore difficulties encountered in doing homework. Of course, the student is expected to come to class and afterward make an effort afterward to understand the material. But certain questions of clarification are best asked as soon as they occur to the student. To facilitate class discussion, you are encouraged to speak up without raising your hand. Simply find a pause in the lecture, as you would in a conversation.