Learning aid is composed of three sets of cards, in flip-over bindings, each printed with a letter or numeral or symbol and which fits into a pocket

摘要

The learning aid is composed of three sets of cards, held together in flip-over bindings, each card being printed with a letter or numeral so that they can be displayed in a variety of combinations. The set is small enough to fit in a pocket, made of wood, plastics, metal, and coated or uncoated cardboard or paper.