If you have a lock with 4 different numbers as the code, each ranging 0-9, how many possibilities are there?

I thought it would 10,000 but one of my teachers was being a c unt and kept arguing. I don't know, I might be wrong but the teacher always is really stubborn about being right. The other day he said the sled scene in Citizen Kane occurred right after the opening but I said there was at least the scene with the News video first. Then he denied there was a scene with the video. Sorry about ranting, but this is supposed to be the video teacher also. Its just driving me crazy.