In this paper, we propose a theoretical tool for analysing mathematical reasoning using Epistemological Move Analysis (EMA) in combination with a framework focusing on arguments and the foundation of these. We also suggest the addition of evaluative arguments when talking about different types of arguments besides predictive and verifying arguments. The tool was applied on data of preschool children’s mathematical reasoning. The results indicate that different types of epistemological moves are connected to the different types of or the lack of arguments, and will fill (or not fill) gaps that occurs in the reasoning.