Apparatus for teaching addition of pairs of one-digit numbers

摘要: Apparatus comprising an educational toy for instructing beginning students in addition of pairs one-digit numbers. Preselected numbers are displayed, each on a different rotating cylinder, or roll. Each roll the pair is scribed with set rotated through series fractional rotations, constant angle, via action drive which rotates similar manner, and turn actuated by keyed slide bars represent answers to problems displayed. When correct key, keyboard, manipulated, rotated, response movement roll, fraction revolution present next problem, signal indicate solution given. No given incorrect solution.