Further confirmation of the fact that "diversity" and the consequent need of didactic diversification represent a precious value.
Broadly speaking, "diversity" is a "broader" concept than "normality", even in the sense (again!) of diversification. If it is difficult to try to structure a didactic framework on the huge pack of individual microcharacteristics that belong to "normality" (which has already required centuries of sedimentation in the history of didactics, not only of mathematics), we can easily imagine what a lot of possible variants can exist in the microchanges in each of them.
The only "H.C.F." between "normal" and "different" people is often represented by "simple" things.