The arithmetic-challenged should avoid this lamp at all costs, because to turn it on, you’re required to correctly solve a math problem. From the looks of this Mingyu Jeung creation, problems appear to be of the simple add/subtract/multiply/divide variety, so you don’t need to be a math major to safely navigate your home. But if you’re really bad at math, look on the “bright” side—you’ll save a lot on your power bill! [Yanko Design]