I wasn't sharp enough to figure out the quiz. Is the whiteboard supposed to be the hint? All I could get there was X+<blob>-? and then there's the red scribble with an arrow pointing up at the first part. Is it my eyes or my brain?
Thanks for the answer! I finally figured it out, although I never did notice a second clue. I just blindly did the operations on the board and smashed the result into the extra number, sort of feeling like this couldn't possibly be right the whole time, but it was!
