Vol. 9 Num. 2 (1989) John Mason Mathematical abstraction as the result of a delicate shift of attention2 Efraim Fischbein Tacit models and mathematical reasoning9 Kev Delaney Inside and outside primary school mathematics15 Eugenio Filloy , Teresa Rojano Solving equations: the transition from arithmetic to algebra19 David Blundell , Rosalinde Scott-Hodgetts , Stephen Lerman Mathematising the hard stuff27 Paul Cobb Experiential, cognitive, and anthropological perspectives in mathematics education32