This study used a holistic multi-case research design to investigate fourth-grade students' skills for solving non-routine mathematics problems. The participants were three 4th grade students (primary school) with low, moderate and high achievement in mathematics respectively, who were educated in the same class at a state school of middle socio-economic level in north-east Turkey. They were selected through a maximum diversity sampling method. Data were collected using a clinical interview technique, via a form consisting of four non-routine problems, developed by the researcher, and were analysed via a content analysis procedure. Findings reveal that participants did not use strategies that can be used during reading problems; although all three students performed the arithmetic operations correctly, they could not reach the correct result in their first stage in both problems; they only checked the accuracy of the result on arithmetic operations. [This study was presented as an oral presentation at the 17th International Primary Teacher Education Symposium.]