Addition and Subtraction Strip Board helps a child understand basic strip, and prepares a child for addition and subtraction math. Aid the child in learning addition and subtraction tables. The set contains: 2pcs Wooden board 12 squares by 18 squares with the numerals 1-18 printed across the top. A wooden box contains 9 red wooden strips and 9 blue wooden strips of varying lengths both printed with the numerals 1 to 9. and a box with 17pcs white strips.