In the 1960s the progressive tradition in mathematics became widespread and an influential statement by one of its leading proponents Edith Biggs (1965). Sold 165,000 copies in there years. During this period the progressive orthodoxy developed, increasing the emphasis on discovery, problem solving and children’s attitudes to mathematics. An influential statement of this philosophy came from the Nuffield Mathematics teaching Project (1965). This emphasized activity through both content and title (‘I do and I understand’), devoted a chapter to discovery learning, and asserted the importance of attitudes to mathematics.