Referring to the ecology of iatromatical problems to the rate interest in mathematical manuals of the sixth form of the primary school, we have realized a descriptive study of the praxeologies used in the most dominant manual, considering the tropical needs connected with. Above the identifications of the praxeologies of that manual, not only have we characterized and evaluated them in following the institutional reports of the national program to the knowledge in study, but also following the aids « arranged » for the pursuit of mathematical activities. The hierarchized praxeologies, traditional, incomplete, and recurrent are pointed out. They inhibit the life of proportional thinking.