Keep Calm And Show Your Work Funny Math Geek T-Shirt Solid colors: 100% Cotton; Heather Grey: 90% Cotton, 10% Polyester; All Other Heathers: 50% Cotton, 50% Polyester Imported Machine wash cold with like colors, dry low heat Perfect gift for anyone who loves funny math puns Our Tee shirts are the perfect gift for someones Birthdays, Family gifts, Christmas presents, or any Special Day. Lightweight, Classic fit, Double-needle sleeve and bottom hem