Personalized Math Teachers Rock Youth T-Shirt. Math teacher's rock with a happy rock holding the numbers one, two and three, is a funny academic gift design for your favorite school teacher at back to school, birthdays and holidays. 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.