DIDUNAS addresses an issue of concern in several countries of the European Union, that is, students’ under-achievement in mathematics. Students who do not achieve a satisfactory level of competence in mathematics are at risk of failing to cope in a numerate society. The overall purpose of DIDUNAS is to address students’ under-achievement in mathematics early in schooling in Grade 1. For this purpose, DIDUNAS develops a digital tool to identify under-achieving students, an App for the identification of under-achieving students, support material for students, material for teachers, and for parents, as well as an e-learning environment, which will host the App and all material.