Math It's Fun & Games Until Someone Divides By Zero 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 Design exclusive to Amazon Featuring men's, women's, and youth sizes Lightweight, Classic fit, Double-needle sleeve and bottom hem