C0 
Exercises where the use of CAS is of little or no help. More importantly, the typing would take more time than solving the problem byhand (this of course depends on the students' skill). 
C1 
Traditional exercises (byhand or using scientific calculators) that are solved faster or even trivialised by CAS (emphasis usually on manual skills). 
C2 
Exercises that essentially test the ability of using CAS competently. 
C3 
Exercises starting from traditional ones that are extended to CASexercises (e.g. by including formal parameters or using realistic data). 
C4 
Exercises that are difficult or time consuming to solve without CAS or those that can only be solved with the aid of CAS. 
C0 
Exercises where the use of CAS is of little or no help. More importantly, the typing would take more time than solving the problem byhand (this of course depends on the students' skill).
