Kids Square Root 10 Years Old Funny 10th Birthday Shirt For Kids 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 for kids who love math! "I am square root of 100 years old" Lightweight, Classic fit, Double-needle sleeve and bottom hem