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