This paper intends to present the design of an intelligent assessment system, which attempts to assess the student in arithmetic word problem solving. During assessment, the system keeps track of the aptitudes, which the student shows, concerning the answers he/she gives to special types of problems and in the same time it observes aspects of the student’s motivational state. More precisely, motivation aspects deal with a) the effort the student shows in solving the different types of problems and b) with the independency and the confidence that characterize his/her behaviour. The system tries to adapt itself according to the above information, in order to motivate the student, offering her the appropriate help and the possibility to follow an individualized way through the objective items of the assessment.