KindKids Super Sudoku: A Super-Cute Book of Brain-Boosting Puzzles for Kids 6 & Up A Super-Cute Book of Brain-Boosting Puzzles for Kids 6 & Up Introducing a fresh and creative approach to kids’ activity books! The KindKids series from Better Day Books combines adorable art, deluxe packaging, and positive messages with classic puzzle activities to create an enjoyable experience that both kids and parents will love.