"<< Objectives >>SIMUL supports multi-grade classes by enhancing the teaching of technical-scientific subjects with the STEAM approach and also promotes digital literacy and environmental sustainability. In 5 languages, it offers a toolkit with 8 STEAM workshops designed to simultaneously engage students of different ages (6-10 years) in various roles, addressing curricular needs. Second output: the ""SIMUL Docere"" guidelines for STEAM teaching in multi-grade classes with a focus on methodologies.<< Implementation >>SIMUL includes: preliminary analysis with survey for teachers; development of SIMUL Toolkit containing 8 workshops based on the STEAM approach, designed for multi-grade classes, with clear instructions on activities to be carried out and any supplementary materials; development of SIMUL Docere Guidelines; teacher training on the two tools and testing of the Toolkit with classes of three different schools, validation, and online publication in 5 languages. Promotion and dissemination activities.<< Results >>Teachers: increased competences in the STEAM approach in multi-grade classes, opportunities to teach through new methodologies, more motivating tools to achieve results on technical-scientific subjects and digital and environmental issues.Students: greater opportunities to participate in classroom activities by interacting in different roles during lessons; increased technical-scientific skills related to the STEAM approach."