One way to characterize students' representations is to distinguish between concrete, semi-concrete, semi-abstract and abstract representations. In a previous study with 6-year olds we surprisingly found that – while solving a combinatorial task - the children who used semi-concrete representations in their documentations were more systematic in the process of finding solutions with less duplications than the children who used semi-abstract representations. As a continuation, we have provided 6-year olds with a specially designed application focused on combinatorial task. The aim of the application is to provide an opportunity to develop an understanding of combinatorics and its systematisation by letting children work within the semi-concrete level. The first results of the study indicate that the children indeed develop significant skills when working within the semi-concrete level, for instance they seem to have obtained a good understanding of what the concept different combinations entails.