Research on math learning can largely benefit from cross-disciplinary approaches, particularly when it comes to studies from the fields of cognitive and education sciences. Specifically, research on math education has the potential to critically complement the study of numerical cognition. In this article, we describe the overlap and specificities of each of these scientific domains. We then illustrate a multidisciplinary approach by discussing our recent study of math learning in kindergarteners within the context of the Montessori pedagogy. We demonstrate how a math education perspective allowed us to design a research methodology that included both quantitative and qualitative methods, to develop new measurement tools, and to interpret the results obtained.