International evaluation studies reveal that in Europe approximately 20% of the young generation is not equipped with the basic skills in mathematics. The latest PISA study revealed that 22% of European students were low achievers in mathematics and the great majority of them can be found in socially disadvantaged areas. This study also reports that 40% of the variation in student performance in mathematics is found between schools within a country. This implies that interventions targeting students’ basic skills in mathematics at the school level are needed. Moreover, research shows that interventions at primary schools supporting children who are at risk have stronger effects. In this context, this project aims to support primary schools in socially disadvantaged areas to use an evidence-based and theory-driven approach to promote students’ basic skills in mathematics. Schools in four countries are supported to develop their own strategies and actions by using a dynamic approach to school improvement, taking into account their context and the specific problems/challenges they face. The proposed approach draws on a dynamic theory on educational effectiveness which has been systematically tested through national and international studies. This theory draws attention to the actions taken at the school and classroom level in order to improve the school learning environment and the quality of teaching. It also refers to quantitative and qualitative characteristics of these factors by giving special attention to the differentiation dimension. Differentiation is not only seen as an aspect of effective teaching, but also as a dimension that should be taken into account in defining school policy for teaching and school policy for improving the school learning environment. Thus, this project draws on experiences of previous studies which show that these factors are associated with student learning and their learning outcomes and aims to promote quality and equity at school level. Schools in socially disadvantaged areas are, therefore, encouraged to identify intermediate objectives concerned with the improvement of school learning environment and school policy for teaching that can contribute to the improvement of learning outcomes in mathematics. Specifically, academic institutions in four countries with an expertise in research on school effectiveness and school improvement will collaborate with about 70 primary schools in socially disadvantaged areas to use the dynamic approach to promote student learning and learning outcomes in mathematics. Schools are supported to establish school evaluation mechanisms to measure school factors and students basic skills in numeracy and identify their improvement priorities. Schools also receive training on the dynamic theory and its use for promoting quality and equity in education. Support to design their improvement strategies and action plans will be provided. In addition, attention will be given to the development of internal mechanisms to monitor the implementation of the intervention in order to continuously adapt their action plans. Finally, a value-added approach will be used to evaluate the impact of the dynamic approach on: a) improving the school learning environment, b) improving school policy for teaching, c) developing students’ basic skills in mathematics, and d) reducing unjustifiable differences in student achievement. Beyond measuring the impact of each strategy, we also investigate the conditions under which the use of an evidence-based and theory-driven approach to promote quality and equity will be effective, in relation to the achievement of basic skills in mathematics in socially disadvantaged areas. Finally, the project will draw implications for improving regional and national policy on promoting equity in education and search for possibilities to expand this approach in other areas in education and other countries.