1992'1, p.60
Atakhanov R. A.
Concerning some diagnostic methods in mathematical thinking development

Mathematical thinking develops from empirical level to theoretical one. The sequence is as follows: empirical (preanalytic), analytic, planning, reflective (theoretical) stages. Mathematical thinking (and its levels) as well as general one can be assessed by a number of methods. Their important feature is their adequacy to age. The development of general and mathematical thinking not always corresponds each other.