<![CDATA[Conceptual understanding of mathematics is essential for prospective elementary school teachers, yet primary school teacher education students face challenges in connecting mathematical concepts with classroom practice. This study examined the implementation of project-based learning (PjBL) through elementary school teaching assistance activities to strengthen students’ conceptual understanding of mathematics. A mixed-methods approach with an embedded experimental design involved 27 fifth-semester students from class 34A at the Faculty of Education, Universitas Negeri Makassar, who participated in teaching assistance at partner elementary schools in Bone Regency. Data were collected through conceptual understanding tests, observations of PjBL implementation, documentation, and student reflections. Quantitative data were analyzed through pretest–posttest comparisons and normalized gain (N-gain) calculations, while qualitative analysis involved data condensation, data display, and conclusion drawing. The mean conceptual understanding score increased from 46.37 at pretest to 87.85 at posttest, with a mean N-gain of 0.764, categorized as high. The activities also provided authentic experiences in designing, implementing, and reflecting on mathematics instruction in elementary schools. These findings indicate improved conceptual understanding following PjBL implementation and highlight opportunities to connect mathematical knowledge with teaching practice. The study supports the potential of integrating PjBL into teaching assistance programs to strengthen the academic and pedagogical preparation of prospective elementary school teachers.]]>
