Achieving Problem-Solving and Sustainability Competencies Through STEM–PBL Waste-Utilization Modules in Inclusive Mathematics Classrooms

Abstract

This study investigates the achievement of a STEM–Problem Based Learning (PBL) module on students’ mathematical problem-solving and sustainability competencies within an inclusive classroom. The module centers on Social Arithmetic and integrates waste-utilization activities to promote meaningful, real-world learning aligned with Education for Sustainable Development (ESD). Designed for diverse learners, including students with mild learning difficulties, the module incorporates scaffolding, hands-on tasks, multimodal representations, and flexible grouping to ensure equitable access to learning. Using a descriptive one-group design, students engaged in STEM–PBL tasks that, although not explicitly framed as ESD instruction, naturally fostered sustainability awareness and responsible environmental behaviors. Expert-validated instruments assessed mathematical problem-solving and sustainability achievement, with adaptations to support inclusive education principles. Data were analyzed using the Respondent Achievement Level (RAL) method. The findings show that students achieved high levels of performance in both domains. The learning process also encouraged active involvement in waste-utilization projects such as creating decorative pots, ecobricks, paving blocks, reusable bags, and producing animal feed from organic waste using maggots. Activities designed to accommodate students with varied abilities. These results indicate that STEM–PBL modules can support problem-solving skills while simultaneously nurturing sustainability competencies in inclusive mathematics settings.