\input zb-basic
\input zb-matheduc
\iteman{ZMATH 2000c.01554}
\itemau{De la Rocque Palis, Gilda}
\itemti{Let's ask "why?" After "what if?".}
\itemso{J. Comput. Math. Sci. Teach. 18, No. 4, 415-437 (1999).}
\itemab
The relative availability and flexibility of spreadsheets make them very attractive, especially in an environment where computer resources are scarce. The present demand for the introduction of computer work in schools and colleges in Brazil has led us to design a set of spreadsheet-supported activities to examine how preservice and in-service teachers behave in an exploratory computer setting and so provide us with clues capable of informing the design of other learning opportunities using this technological tool. We describe the content of the activities devised and add some questions that arose from our previous survey of the literature, in particular the question relating to the need believed (or not believed) by teachers to justify numerical or graphical computer results. We also describe some of the strategies used by teachers in carrying out certain of these activities. The results of this initial investigation indicate that the idea that particular numerical results are not synonymous with proof may need to be emphasized through activities in which one explicitly asks ``why'' after ``what if'' questions when working with teachers, especially with practising teachers.
\itemrv{~}
\itemcc{B50}
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\itemli{}
\end