Two other papers were focused on the question of geometrical reasoning. Georgia
Panoura and Athanasios Gagatsis underlined that the geometrical reasoning of
primary and secondary school students can be compared mainly on the way students
confronted and solved specific geometrical tasks: the strategies they used and the
common errors appearing in their solutions. This comparison shed light to students’
difficulties and phenomena related to the transition from Natural Geometry (the
objects of this paradigm of geometry are material objects) to Natural Axiomatic
Geometry (definitions and axioms are necessary to create the objects in this paradigm
of geometry). They stressed the inconsistency of the didactical contract implied in
primary and secondary school education and they conclude on the need for helping
students progressively move from the geometry of observation to the geometry of
deduction.