5. Some of the rationales for emphasizing mathematical activity are that “in studying mathematics it is important for learners to deeply experience various phenomena through activities such as observing, manipulating and experimenting. It is also important for students to refine their understanding through activities such as reflecting, representing or expressing themselves by using mathematical language, and through repeated close examination”. In addition to the knowledge obtained through those mathematical activities, the approaches, methods or perspectives which students also experience in constructing new knowledge are very valuable. They may become effective tools for problem-solving, they may lead to the discovery of new problems and they may also become a mean to extend knowledge into new areas.