His study attempts to describe a mistake in doing the students based problems by using the theory newman.This kind of research with a qualitative approach, is descriptive the data collected by providing about based the written material. set of problemsThe subject of this research is a student junior high school class vii.The results of the data in get according to the theory newman students made a mistake classed in some kind of mistake of them read error, a mistake, understand the problems a mistake, transformation a mistake skills, process and a clerical error. final answerStudents who have made a mistake to the process at first would be wrong too when going to keep the next process.If you see from the fact this research can be inferred students most often made a mistake the skills of the process of it is a major influence on the writing of the final answer.