Vol. 16 Num. 1 (1996) Helle Alrø ,  Ole Skovsmose On the right track2 David Slavit Graphing calculators in a hybrid Algebra II classroom2 Eileen Phillips ,  Sandra Crespo Developing written communication in mathematics through math penpal letters15 Orit Hazzan ,  Uri Leron Students' use and misuse of mathematical theorems: the case of Lagrange's theorem23 Kev Delaney Exploring difficulties in teaching mathematics through investigations in the primary classroom27 Jane-Jane Lo ,  Kelly Gaddis ,  David Henderson Building upon student experience in a college geometry course34