A digital wall is a tool for students to structure and register their online work on mathematical problem-solving activities that involve the coordinated use of digital technologies. How could students use such digital wall to understand mathematical concepts and to develop problem-solving competencies? The aim of this study is to analyze and document the extent to which the students' use of the wall became a powerful tool to share, discuss, and refine their problem-solving approaches. To this end, the development of the sessions was structured around principles that foster an inquiry method that privileges the participants' formulation of questions; the systematic and coordinated use of digital technologies, and a support system for students to face technical and content questions. Results indicate that the use of a digital wall became a powerful tool for the participants to report and share their ideas and problem-solving approaches to refine and extend their solution methods. [For the complete proceedings, see ED658295.]