Personalized Happy Pi Day Math Lover Party Women's V-Neck T-Shirt. Pi Day math themed Women's V-Neck T-Shirt - Black has pi symbols in a pie. Fun gift for a geek, math teacher, college math major or any math lover. 5.0 oz., 100% pre-shrunk cotton Athletic Heather is 90/10 cotton/polyester 1x1 rib collar with mitered v-neck Shoulder-to-shoulder taping Ladies' fit