Designing algebra learning using the realistic mathematics education (RME) approach for addition and subtraction of algebraic expressions

Source abstract

Algebra at the junior high school level is often perceived as difficult, abstract, and meaningless because it is usually taught procedurally and without connections to real-life situations. However, few studies have designed a Hypothetical Learning Trajectory (HLT) for algebra using culturally relevant contexts. This study aims to design instruction on the addition and subtraction of algebraic expressions based on the Realistic Mathematics Education (RME) approach by developing an HLT that uses traditional market snacks as the learning context. The participants were 29 Grade VIII students of SMP TMI Roudhotul Quran in Metro City. The study employed a validation design research approach consisting of the preliminary design and pilot experiment stages, followed by a retrospective analysis. The resulting HLT comprises four main activities: context exploration, introduction of variables, manipulation of algebraic expressions, and generalization. The implementation shows that snack contexts, such as onde-onde and lemper, help students make sense of mathematics through real-life situations; students moved from thinking about “3 lemper” to writing the algebraic expression 3a. Students then developed an understanding of variables, coefficients, and constants; classified and operated on like terms in the addition and subtraction of algebraic expressions; and worked symbolically without relying on concrete contexts, an indicator of vertical mathematization. Overall, this RME-based instructional design helps reduce misconceptions, increase accuracy, and strengthen students’ conceptual understanding of algebra, making it a promising alternative learning strategy for algebra in junior high school.