From new math Pempek context to critical thinking: Developing a local instructional theory of social arithmetic through Indonesian Realistic Mathematics Education

Abstrak

Social arithmetic is an important subject in mathematics education because it is closely related to financial literacy and economic activities in everyday life. However, students still have difficulty understanding social arithmetic concepts, such as profit and loss percentages and discounts, which require critical thinking skills. This study aims to develop Local Instructional Theory (LIT) on social arithmetic material through the Indonesian Realistic Mathematics Education (PMRI) approach using the New Math Pempek context to train students' critical thinking skills. This study uses a validation study type of design research method, which includes three stages, namely preliminary design, design experiment (pilot experiment and teaching experiment), and retrospective analysis. The research subjects consisted of ten students in the pilot experiment stage and twenty-five seventh-grade students in the teaching experiment stage. The results showed that the developed LIT consisted of three learning paths, namely (1) capital, selling price, and profit, (2) percentage of profit and loss, and (3) discounts and double discounts. The use of the New Math Pempek context enabled students to engage in contextual and meaningful learning through project activities and problem solving, thereby facilitating the emergence of critical thinking skills, including interpretation, analysis, inference, and evaluation. These findings indicate that PMRI-based LIT with a local cultural context can support conceptual understanding of social arithmetic while also training students' critical thinking skills.