<![CDATA[This study aims to comprehensively analyze the enhancement of students’ mathematical literacy and problem-solving abilities through inquiry-based learning within the framework of the International Baccalaureate (IB) Primary Years Programme (PYP) at SD Al Firdaus Surakarta. The research uses a descriptive qualitative approach with a case study design, involving one mathematics teacher and twenty-one fifth-grade students selected through purposive sampling. Data were collected through participatory observation, semi-structured interviews, and document analysis, and validated by triangulating sources and methods. The results indicate that inquiry-based learning implemented through the stages of tuning in, finding out, sorting out, going further, and reflecting encourages active participation, conceptual understanding, and students’ reflective thinking in mathematics learning. Students demonstrate improvement in mathematical literacy, specifically in the aspects of interpretation, representation, and reflection, as well as in problem-solving abilities according to the four Polya stages: understanding the problem, devising a plan, carrying out the solution, and looking back. The teacher acts as a facilitator, guiding students’ thinking processes through reflective questions and connecting concepts to real-life contexts and local Islamic values. Despite challenges such as varying numerical abilities and the need for additional time, adaptive strategies, including guided inquiry and differentiated support, have been employed. The study demonstrates that inquiry-based learning enhances logical reasoning, fosters metacognitive awareness, and promotes contextual, reflective, and student-centered mathematics learning by integrating global IB principles and local Islamic values as a holistic primary school learning model. Keywords: Inquiry-based learning, mathematical literacy, problem solving]]>
