Personalized Happy Pi Day Robot Math Class Toddler Full Zip Hooded Jacket. Pi Day Toddler Full Zip Hooded Jacket - Black has funny vintage style robot and math symbol Happy Pi Day celebration logo. 7.5 oz., 60/40 cotton/polyester. Jersey-lined double-needle hemmed hood. Pouch pockets for all their treasures. Coverstitched shoulders and armholes. Coverstitched rib waistband and cuffs.