Children today live in a world that is characterised more and more by electronic media. These appeal primarily to the senses of sight and hearing. There is the danger that these senses are used one-sidedly while the others atrophy. Schools and nursery schools should counteract by supporting learning with all senses. In Montessori Education, the child is fostered by actively dealing with concrete teaching material that appeals to all the senses in different ways. Concepts are founded on concrete sensory experience and the child’s active doing and are thus made understandable. This can be illustrated particularly well with Montessori’s mathematical material. The child progresses from physically grasping to mentally grasping. What is important is not only the element of illustration but also — as the developmental psychologist Jean Piaget has shown in his research — the concrete operating, the active doing.