Analysis of understanding mathematics concepts of junior high school students on the subject of coordinate systems

This qualitative research with a descriptive approach aims to find out how junior high school students understand mathematical concepts on the subject of the coordinate system, and is carried out at SMPN 1 Gambut in the 2018/2019 academic year. The subjects of this study were all 28 students of class VIII H, who then selected 9 people with the distribution of 3 students each with high, medium and low abilities based on the student's academic ability. The research data was obtained from a written test sheet type of description that has been validated and interview result. Of the seven indicators of conceptual understanding that were created, they were analyzed in order to obtain an overview of which mathematical concepts had been mastered and which had not. The results showed that students with high academic ability had not mastered giving examples and non-examples of a concept, students with moderate academic ability had not mastered three indicators other than the same indicators as students with high academic ability, namely classifying objects according to certain characteristics according to the concept, presenting concepts in various forms of mathematical representations, and applying concepts or algorithms to problem solving, while students with low academic abilities have not mastered one additional indicator other than students with moderate academic abilities, namely about using and utilizing and selecting certain procedures or operations.