‎The importance of Problem Solving (PS) has been realized for such a long time that in a direct or indirect way affects our daily lives in many ways‎. ‎Assessment cases appear frequently for PS skills which involve a degree of uncertainty and (or) ambiguity‎. ‎Fuzzy logic‎, ‎due to its nature of characterizing such cases with multiple values‎, ‎offers rich resources for dealing with them‎. ‎On the other hand‎, ‎Fuzzy Numbers (FNs) play a fundamental role in fuzzy mathematics‎, ‎analogous to the role played by the ordinary numbers in classical mathematics‎. ‎In the present paper we utilize the two simplest forms of them‎, ‎i.e‎. ‎the Triangular and Trapezoidal FNs‎, ‎together with the Centre of Gravity (COG) defuzzification technique as assessment tools for PS skills‎. ‎Our results are illustrated by three examples in which the assessment outcomes of FNs are validated through their comparison with the corresponding outcomes of assessment methods of the bi-valued and fuzzy logic already tested in author's earlier works‎. Manuscript profile