Math Joke Gift design. Fans of math, space, sci-fi, and all things nerd culture: rep your fandom with pride. Mathemticians know how to drink beer - under a square root! When you take the square root of beer, you get "root beer". Hilarious and delicious! Catch a laugh from your friends when you wear this out to your next party, pub crawl, or bar night. Lightweight, Classic fit, Double-needle sleeve and bottom hem