Interactive whiteboard offers a high-potential innovative tool in mathematical educational environments, in which teachers' modeling processes and students' exploring activities can easily be executed. Nevertheless, these affordances are not self-evident. There is a gap between the potential claims of the tool and its actual use in the classrooms. This study investigated, through two parallel case studies, the interactive whiteboard potential in view of optimizing the exploitation of the interactive whiteboard, improving conceptual understanding, and fostering interactivity in secondary mathematics classrooms. Two main patterns for a productive interactive whiteboard use emerged: (a) a "problem-solving" pattern consisting of interactive whiteboard supporting problem-solving activities and (b) an "organizer" pattern consisting of using interactive whiteboard as a kind of advanced organizer and stimulating students' reflection and mathematical contributions. The two patterns were used to design and teach lessons that were analyzed through the instrumental orchestration framework elaborated by Drijvers, Tacoma, Besamusca, Doorman, and Boon. Analysis showed how the interactive whiteboard acted as a useful instrument for students' discussion and collective construction of mathematical knowledge.