Montessori mathematics teaching material Seguin Boards, suitable for babies over 3 years old. Teach your baby to recognize 1-19 and 11-99 consecutive numbers correctly Help children grasp the arrangement of consecutive numbers and understand the sequence of consecutive numbers Understand the relationship between tens and ones, and the consistency between quantity and the symbol "number" representing quantity Commitment: if you receive damaged goods or have any questions about the goods, you can contact us first, and we will definitely give you the most satisfactory solution