A jigsaw unit is a type of educational tool used to teach problem-solving skills. It consists of a set of interlocking pieces that can be arranged to form a picture or pattern. The term 'jigsaw unit' comes from the fact that the pieces must be put together like a jigsaw puzzle in order to complete the task. The pieces are usually made of wood, plastic, or cardboard and can be used to teach a variety of topics, such as math, science, language arts, and history.