Résumé In this presentation we summarize the ongoing process of the ICMI STUDY 23, from the launch of the Discussion Document in April 2014 to the Conference (held in Macau in June 2015). From the very beginning the study appeared as a world wide effort: the ten IPC members were appointed from the five continents, plenary speakers were chosen from three different cultures and professional experiences, participants were selected from as many contexts as possible and panels were constructed with the involvement of people from different cultural backgrounds. The Conference venue was chosen in Macau, as the meeting point of East and West some centuries ago. It is the fist study launched by ICMI to address primary school teaching and learning. It is a challenge against the belief in universality of mathematics and didactics of mathematics which seems to be shared by many educators in the West, as if the theory and practice of teaching and learning mathematics might repel contexts and the findings of studies might be applied everywhere.