@ARTICLE {, title = {Skúmanie v školskej matematike – Magický štvorec a mobilný telefón}, author = {Frobisher, Leonard and Kopka, Jan and Trenkler, Marián}, journal = {Obzory matematiky, fyziky a informatiky}, year = {2007}, volume = {36}, number = {1}, pages = {6--14}, issn = {1335-4981}, abstract = {Investigation is not only a method for a teacher to use in teaching mathematics, but also for a student to use in learning the subject. We show how to construct a magic square using the numbers on a cellular phone with the help of investigation. We then consider how the same problem can be approached in the early years of elementary school giving rise to many related problems.}, }