Arithmetic PuzzleThis is truly an educational puzzle Designed by a teacher, this clever area based puzzle teaches addition with just 10 pieces. Note that the "two" piece is twice as big as the "one"? If the two and the one are laid atop the "three" piece, they match the size and shape of the three, and so forth. All the combinations work. Puzzle People's ARITHMETIC Puzzle is BILINGUAL English, Spanish, and counting dots are imprinted on the tray under each piece.