The implementation of mathematics learning in Grade III primary school still faces various obstacles, such as students’ difficulty in understanding basic mathematical concepts, low motivation to learn, and lack of skills in solving word problems. These problems are usually caused by a teacher-centered learning approach that tends to focus on memorization. This study aims to explore the problems that arise in the process of teaching mathematics in third grade elementary school and proposes a Project Based Learning (PJBL) model as a creative solution to increase student participation and understanding. The research method applies a descriptive qualitative approach with data analysis techniques according to Miles and Huberman, which include data reduction, data presentation, and conclusion drawing. The research findings indicate that the implementation of PJBL result in a more relevant, meaningful, and exciting learning experience for student. Through projects, students actively participate in solving real-word problems related to mathematical concepts, such as pattern calculations, fraction, and creating simple models using concrete objects around the school area. This innovation not only deepens conceptual understanding but also encourages the development of critical thingking, collaboration, creativity, and student confidence. In addition, PJBL is in line with the principle of the Merdeka Curriculum, which makes students active subjects in the learning process and teachers facilitators. Overall, the study shows that the PJBL model is effective in mathematics learning in primary schools to increase motivation, conceptual understanding, and the quality of student learning outcomes.