ABSTRACT
This chapter presents an approach to the teaching of fractions that takes the role of magnitudes into account and aims at moving children's conceptions one step further, to the understanding of fractions as operators. It suggests an answer to the question that explains how people can guide primary-school children in their attempts to master an operational concept of fractions which is applicable in all its operational aspects. The way fraction-provoking fair sharing was interpreted as a model is partly based on Piaget's work. Streefland examined how the context of fair sharing can have a long-term role in the teaching, learning process, both through the sharing activities and the material operated on. The relationship between fair sharing and fractions is not a question of concretising or illustrating some mathematics but of mathematical activities and mathematics evolving from sharing activities. It concerns the constitution of mental objects, instead of the attainment of concepts.
