This study presents KIDEDU (Play—Create—Learn), a digital game-based learning initiative designed to support mathematics and environmental education in Greek primary schools. Grounded in the principles of differentiated instruction and guided discovery learning, KIDEDU integrates interdisciplinary content from mathematics, geoscience, and everyday problem-solving into an engaging and culturally relevant digital environment. The project targets children aged 6–12 and is structured across three levels corresponding to the primary school curriculum. Empirical results from pilot implementation show that pupils engaged actively with the game, demonstrated enthusiasm, and developed effective problem-solving strategies both individually and collaboratively. The majority of participants reported that the game made learning mathematics easier and more enjoyable, with high levels of willingness to replay and recommend the experience. These findings highlight the motivational benefits of educational games, as well as their capacity to enhance conceptual understanding, critical thinking, and peer collaboration. KIDEDU exemplifies how digital, game-based learning environments can serve as effective tools for differentiated and inclusive instruction, shifting teachers’ roles toward facilitators of exploration and inquiry. The project contributes to ongoing efforts to innovate mathematics education in Greece and has the potential to be expanded to other subjects and educational levels.