Vol. 7 Num. 3 (1987) Raffaella Borasi Exploring mathematics through the analysis of errors2 Ewa Puchalska , Zbigniew Semadeni Children's reactions to verbal arithmetical problems with missing, surplus or contradictory data9 Alain Bouvier The right to make mistakes17 Mary Harris An example of traditional women's work as a mathematics resource26 Guershon Harel Variations in linear algebra content presentations29 Pearla Nesher Towards an instructional theory: the role of students' misconceptions33 Gert Schubring On the methodology of analysing historical textbooks: Lacroix as textbook author41