Montessori believed that children have mathematical minds and she revolutionised the way in which mathematics is taught. She developed a wonderful set of materials, many of which have now been copied by educators throughout the world. The mathematical concept is presented firstly in a very concrete form followed by the abstract written version. The materials for mathematics introduce the concept of quantity and the symbols 1 through to 10. Then, using a variety of beads and symbol cards, the child becomes familiar with the numbers as a decimal system by means including concrete experiences with the operation of addition, subtraction, multiplication and division. These operations not only teach the child to calculate, but they provide a deep understanding of how numbers function.