Personalized Math Teachers Rock Newborn Layette. 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. 100% combed ringspun cotton 5.8 ounce 1×1 baby rib sleeper. 3/8" flatlock binding at envelope neck and cuffs. Back sleeve flap to protect hands. Elastic opening at bottom. Infant: 0-3 Months