What is the "proper" way of addressing your professor?

<p>Some of my professors don’t care if we call them by their first names. We usually end up working with them on different projects for the department so I guess we have a different relationship with our professors than a lot of students. It is weird though. </p>

<p>Otherwise I just say “professor” whoever. I just don’t assume they’re a “Dr.” though. I’ve done that before and felt bad when I was wrong, lol.</p>