In this article, our goal is to design a suitable strategy to be implemented on High School students in order to prepare them for the formal study of approximate and exact integration via a Socratic semi-structured interview. Our dialog will be closely dependent on the use of a computer generated tool (applet) to encourage students� participation, provide them with numerical and visual data and allow the linking of the processes of discovery, understanding and conceptualization in the frame of an educational model. What follows contains a description of the interview which is also our instrument for pointing out and detecting the levels postulated by van Hiele�s educational model.