Learn mental arithmetic using the Japanese abacus. The package contains an exercise book, a basics book (for children), a notebook to practice speed writing, a notebook to practice hearing, an abacus, and flash cards. Leco Mass is suitable for ages 5 and above, as you learn how to use the abacus and solve mathematical equations such as multiplication, roots, and fractions using only your mind. To get the educational videos, scan the QR code.