Problem solving is an essential part of teaching and learning mathematics, but it poses many challenges for students. We conducted two collaborative research projects involving various educators to co-construct interventions that promote the development of student control during problem solving in elementary mathematics. The analysis of the discussions during the meetings revealed three interventions by the teachers that were influenced by their work in French. This paper presents this reinvestment in mathematics of what is done in French, and discusses possible links between these two disciplines in order to develop students’ interdisciplinary control.