Multimedia technologies, encompassing images, animations, and sounds, offer innovative possibilities for preschool educators, particularly in the context of presenting mathematical content and fostering children's mathematical cognition. This study is driven by a dual objective: firstly, to formulate a GeoGebra-based model for the assimilation of fundamental mathematical concepts related to numbers and sets; secondly, to execute this model in practical educational settings. The research conducted for this paper spanned five years (2018-2023) as part of a comprehensive five-year project, comprising three distinct phases, each featuring specialized workshops. A cohort of 380 preschool teachers completed GeoGebra training, which was followed by the integration of the proposed model into the educational curriculum across preschool institutions in two districts within the Republic of Serbia. Preschool educators independently implemented two activities aligned with their project themes. The study's findings emphasize the effectiveness of implementing an interactive project-based learning approach in preschool settings, where well-integrated GeoGebra applets, particularly when harmonized with activities involving physical and tangible elements, can yield positive outcomes.