Aspetti Matematici del Tangram

In this work we have tried to give an example of how one, through creative games, can fmd a tangible verification of studied notions, receive stimuli and motivations for the study of Mathematics and directly be begun, in a natural way, to the pleasure and the methodology of the research. In particular we have tried to make the reader discover or revisit with new eye topics such as: homotheties, graphs, convex sets, isometrics and tessellations of the plane. Other hints for a use of the Tangram in the Didactic of Mathematics are presented in Pellegrino C., Spigolature sul Tangram, in D'Amore B. (ed.), proc. Naz. Meeting "Gioco e Matematica", Cappelli, Bologna, 1986, 82-94. These didactic indications have been developed in a didactic experimentation that has enabled the pupils to recognise, in a concrete way, symmetries, similarities (and then find ratios of similitude) or possible compositions of elementary isometrics and moreover to verify algebraic equalities through different calculation of the same areas. The activities done has also encuraged in the pupils reflections on what is a proof and in particular has solicited them to: i) find the spur to face problems, pose themselves some new ones, make hypotheses, verify them or find; ii) understand what is a proof of non-existence, a paradox and an open problem. These results have been collected in Pellegrino C. and laderosa R., Un'esperienza di utilizzo del Tangram in attività di Matematica per la scuola media, MD, vol.4, n.3,1990, 5-11.