[b]Pre-service Teachers[/b][br][br][b][color=#0c343d]Department of Computer Science [/color][/b][br]http://kafinfo.org.ua/[br][br]Faculty of Physics and Mathematics [br][b]G.S.Scovorodu Kharkiv National Pedagogical University[/b][br]UKRAINE[br][color=#0000ff][br][b]GeoGebra Institute of  Kharkiv[/b][/color][br][br][i]Author: [/i]Valentyna Pikalova[br]vpikalova@hotmail.com