Perfect Arithmetic - Gakken Popular Keywords: Gakken Popular Keywords: Kodomo Challenge Batteries Required This is an educational toy from Gakken that allows children to easily learn how to read clocks, read numbers, and practice addition, subtraction, multiplication, division, and play games. There is some sun damage and wear on the sheets, but it does not affect the operation. For young children to elementary school students Type: Numbers Popular Keywords: Gakken Popular Keywords: Montessori Popular Keywords: Gakken Popular Keywords: Kodomo Challenge