Personalized Math Brain Youth T-Shirt. Math text with a happy brain is a humorous design for mathematicians, students and teachers of math. Fun gifts for birthdays, holidays, back to school and graduation. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.