Personalized Pi Day Party Funny Math Toddler Long Sleeve T-Shirt. Funny math design has Pi Day symbol in a slice of pie on this humorous math lover Toddler Long Sleeve Tee - Black. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.