Yuni Arrifadah, Abadi, Raden Sulaiman
Reasoning and proving are mathematical activities. However, engaging students in formal deductive proofs early is inappropriate for child development. Reasoning and proving the definition and classification of a parallelogram, which is simple and not as rigorous as formal proof, is still difficult for students. This is due to students' limited understanding. Collective argumentation was chosen for defining and classifying parallelograms because it clearly illustrates the details of the proof process in defining and classifying parallelograms through argumentation. Argumentation as a starting point for learning proofs is important for building mathematical understanding. Learning through discussion benefits students, including exchanging opinions, negotiating, and agreeing on decisions. This study aims to investigate how students define and classify parallelograms in collective argumentation. This study uses a qualitative approach. The subjects were five groups; each group consisted of three or four students from grade 7 at a middle school in Gresik. Each group is tasked with defining and classifying quadrilaterals and discussing them. The teacher accompanies the discussions to a limited extent, and video recordings are made. This is done so that all arguments are observable and can be repeatedly observed to obtain data validity. The results of the video recordings were transcribed and analyzed using the Krummheuer diagram adapted from Toulmin. The research results show that (1) the student-made definition of a parallelogram still uses the wrong word because the constructed definition is observed through the student-made images; (2) The argument structures that appear in the classification of parallelograms are data, warrant, backing, and claim. Warrants used in collective argumentation are inductive warrants. © 2025 Author(s).
Mathematics Education, Universitas Islam Negeri Sunan Ampel Surabaya, Jl. A. Yani 117, Surabaya, 60237, Indonesia; Mathematics Education, Universitas Negeri Surabaya, Jl. Lidah Wetan, Surabaya, 60213, Indonesia
