Abstract
Many key aspects of modern theory relating to classroom discourse in mathematics education, especially the theory of didactical situations, have not progressed much further than theories put forward in the 1840s by the North American educator David Page. Aspects of Brousseau’s (1997) description of what he called the Topaze effect, are remarkably similar to Page’s idea of “drawing outâ€â€”a mode of questioning that was likely to remove the cognitive challenge for learners engaged in non-trivial mathematical tasks.
Nerida F. Ellerton, Pongchawee Vaiyavutjamai & M. A. (Ken) Clements