摘要：This study aims to analyze: (1) The level of students' mathematical problem-solving ability, (2) Mistakes made by students in solving mathematical problem-solving problems. This type of research is qualitative research. The subjects of this study were students of class VII-A at Tunas Baru Jin Seung Middle School, Batam City. The results showed that: (1) High-ability students were able to carry out the stages of understanding the problem, devise a plan, carry out a plan and look back. Moderate-ability students are being able to carry out the stages of understanding the problem, devising a plan, and carry out a plan. While low-ability students can carry out the stage of understanding the problem. (2) Students can understand the problem by writing down what is known and asked, but unable to explain in their sentences. Students are not able to devise a plan because of the inability to associate information with one another. Students are not able to carry out a plan, this is due to the inability of students to make plans so they do not understand how to solve problems and calculation errors occur in the completion process. Students are not able to look back obtained and give their arguments.
