Kiddo loves playing around with numbers. likes to use his Montessori decimal number cards to make numbers he finds in books. He found the space section at the library and has been bringing home books about the planets. They have a lot of big numbers in them. So, of course, he has to make them.He gets so much mileage out of these number cards. He is also fond of recreating the numbers in his sudoku book. They were one of the best purchases ever.