[i]1. [/i][i]Students progression on algebraization levels:[br] - Childhoord Education: dragging and moving points.[br] - Primary Education: generalized numbers, changing numerical values (from level 0 to level 2)[br] - Secondary Education: use of parameters (from level 3 to level 4).[br][/i][br][i]2. Integration of material supports, suitability of the learning process (treatment + conversion)[br][br]3. Influence of dynamic geometry software on the didactical contract (imitation contract - explorative model)[/i][br][br][br]