Improve children's interest in learning. 100 The self-made problem solver for elementary school mathematics addition, subtraction, multiplication and division can improve children's interest in hands-on learning. The production is simple, and only two paper tubes are needed. Teaching AIDS refer to models, objects, specimens, instruments, charts, slides, etc. Used to describe something, including teaching equipment, teaching instruments, training equipment, educational equipment, experimental equipment, teaching specimens, teaching models, etc.