Since there is a shortage in higher educated individuals in STEM all over Europe, and society requires STEM-literacy, more attention should be paid to this issue from early school years on. Consequently, in many EU-countries STEM is prioritized at the educational agenda. Some projects have already focussed on specific aspects of STEM, e.g. inquiry-based science education, but the integrated aspect and its possibilities remain mainly neglected. Furthermore, the potential for STEM-integration in advancing math learning is still less apparent than for science, technology or engineering. As a result, in this project, we put forward an approach of integrated STEM-education and its value for math learning. Additionally, an important argument for this focus is that our educational systems emphasize the use of language, whereby we often do not see the strengths of children for math learning, when they are less talented for language. Furthermore, one of the biggest problems in STEM-education is that children often do not see the link between abstract STEM-insights and their impact on solving real-world problems. That can be the reason why few young people, especially girls, consider STEM-professions. (Sjøberg & Svein, 2008) In this project we point out the idea that an integrated STEM-approach can offer an answer to these issues: based on key elements of effective STEM-education, such as learning by action (doing) within meaningful contexts, it becomes possible to capture the potential of all children, whereby they can learn ‘difficult’ abstract concepts e.g. regarding math learning. Because the different STEM-disciplines are offered in an integrated way to solve problems, which connect to relevant contexts, and wherefore solutions are sought through an iterative process of design and inquiry, a strong connection is made between abstract insights and concrete experiences of the children. Consequently, the meaning and relevance of STEM-disciplines becomes more clear, which can stimule the attitude of children to STEM. Within this project we will use ‘educational design research’ methodology (Mc Kenney & Reeves, 2012) to search for solutions and knowledge regarding these issues. Firstly, we will design and share a didactical model for integrated STEM-education with a clear incorporation of mathematics (IO1). Therefore, a literature study will be conducted, which has already started within the partnership. In the model a strong emphasis will be put on key elements of effective STEM-education (Van Houte, et al., 2013; Van De Keere & Vervaet, 2014). This model will be the guideline for partners to collect, select, exchange and develop STEM-activities. Next, the developed activities will be tested by pilot teachers in the different partner countries. Thus, in the project an iterative evaluation of the intervention (here: implementation of the STEM-activities) will occur to gather information about what works (or not) and about the constraints (Reason & Bradbury, 2001). Results of this testing will be exchanged during joint staff training events (C1, C2) and will be used to optimize the activities so that they become good practices for teachers all over Europe regarding math learning based on an integrated STEM-approach (IO2).A difference will be made between 2 age groups, as children in the last years of primary school are in particular vulnerable to a drop of their attitude to STEM (De Meyere, 2013). Therefore, in the project 10 STEM-good practices will be developed for 9-12 years old, and subsequently, 10 for the age group of 6-8 years. The peculiarities of each age group will be taken into consideration based on the exchange of expertise and experience of the pilot teachers involved in the testing of the STEM-activities (at least 2 in each country for each age group).The didactical model and the STEM-good practices will be integrated in an interactive online learning environment (IO3), and will be enriched with analysis and reflection tasks, so that teachers are enabled, or at least stimulated, to obtain and apply didactical principles within their own practice instead of only executing the offered STEM-activities. This learning environment will be used during national training courses (E1-E5) by each partner (30 participants per country), and of course the learning environment will be open to all teachers who will be able to use it independently as a source of excellent information for an integrated STEM-approach regaring Math learning, even after the project period.At the end of the project a practice-oriented research article (IO4) will be written about the research findings of the STEM4MATH-project.Overall, we expect a shared focus among teachers over the different countries and communities, resulting in the spread of a well-balanced integrated education in STEM, in which difficult math concepts are profoundly enclosed, and consequently, become easier to learn by children in elementary schools across Europe.