That strikes me as an obnoxious professor. What conceivable reason could there be for a college instructor to do that? I only took a few courses before I with

That strikes me as an obnoxious professor. What conceivable reason could there be for a college instructor to do that? I only took a few courses before I withdrew, but the math instructors always assigned problems with solutions for homework, that way we could tell if we didn't understand something and ask about it in class.