Abstract
The paper describes the experiments carried out within the frame of action research. It illustrates pupils' cognitive processes in the geometrical environment Cube buildings.
The tool of the experiment is a geometrical problem involving 3D shapes and their 2D representations and also combinatorics. The strategy that a pupil developed to solve the problem is introduced and its impact on solving strategies of other solvers is described.
The generalization the pupil's strategy to more difficult situations is discussed.