To develop the pupils‘ intellect, to contribute to an effective knowledge of school subjects, it is necessary to develop their operational thinking and judgment. It is characteristic of primary school children a reversibility of their thinking as, a new formation in their age development. It is necessary that this quality should be stimulated but not blocked in their teaching process. All school subjects suppose an active use of thin king operations: analysis, synthesis, comparison, generalization, concretion. The other is the situation now these operations are stimulated and developed in the teaching activity of every school subject. The psychologists suggest including the rational methods of thin king of the efficient development of knowledge in the work with theoretical notions. This would prevent the mechanical learning that doesn’t contribute to the intellect s development.