This explorative study was aims to identify the types of mistakes made by junior high school students using Newman procedures. This study was also aims to overcome the mistakes made by students. The study was focused on three subjects of grade eight junior high school students. The instruments used in this study were PISA tests and interview. Subjects were asked to solve the problem then their answer sheets were analyzed qualitatively. To determine the cause of students’ errors, interviewed each subject based on the work done. The results showed that the type of error made subject 1 was a mistake of comprehension, transformation error. The types of errors to subject 2 were the errors of comprehension, transformation, process skills. Meanwhile, the type of mistake made by subject 3 is a misunderstanding of comprehension, and transformation. To overcome the mistakes made by students, they were are given scaffolding based on the type of mistakes made the subject. Scaffolding given were reviewing, explaining, structuring and developing representational tools.