DOES THIS ADD UP? Chicago-based National Louis University offered a steep tuition discount on Groupon on Tuesday. The university's deal is a nearly 60% discount for a three-credit introductory course that is part of a graduate degree in teaching. It's available for 15 takers (students) and will close by the week's end. Groupon's magic has long been about coaxing consumers to try oh, say, eyebrow threading and eyelash extensions by offering a can't-be-beat deal. Seems an odd way to convince people to become teachers. We wonder how many will click on the "Buy it for a friend!" option? (Groupon, meanwhile, said Monday it is reevaluating the timing of its IPO. Blame the markets? Or Groupon managers odd attitude toward the sacrosanct pre-IPO quiet period? Here's what VentureBeat said about it.)