Personalized Math Tribe Math Department Long Sleeve T-Shirt. Fun back to school math themed design says Math Tribe for a teacher or student. Pre-shrunk 100% cotton 6.1 ounce long sleeve t-shirt. Double-needle stitched neckline and sleeves. Quarter turned. Shoulder-to-shoulder taping. Adult: S, M, L, XL, 2XL, 3XL