Personalized Math Genius Frog Toddler Long Sleeve T-Shirt. A happy green frog holding a banner that reads Math Genius is a humorous gift design for mathematicians, math school teachers and students. 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.