Personalized Math Genius Frog Youth T-Shirt. A happy green frog holding a banner that reads Math Genius is a humorous gift design for mathematicians, math school teachers and students. 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.