The objective of this study was to evaluate and characterize the argumentation patterns used by seventh-grade students in the context of algebraic addition and subtraction problems. A qualitative case study was conducted using the Claim-Evidence-Reasoning (CER) model (McNeill & Krajcik, 2008) and argument quality framework. To describe the arguments put forth by the participants, a sample of ten students with high mathematics proficiency and ten students with low mathematics proficiency were selected from the target population of junior high schools in a large region of West Java, Indonesia. Data collection was carried out using written argumentation frame for algebraic operations (AFAO). The results revealed that, although none of the students employed the CH+EH+RH pattern (which represents the highest quality of arguments), students with high mathematics proficiency levels exhibited a greater prevalence of these argumentation patterns compared to those with low mathematics proficiency levels. The findings have implications as a valuable resource for teachers in monitoring the advancement of their students and preventing or alleviating diverse difficulties or inaccuracies that they may face. Based on the findings, a specific design for a classroom teaching activity is proposed.