f. rashedi

Understanding negative numbers and doing operations on them is one of the fundamental subjects in mathematics that students face many problems when they encounter them at school. One of the problems that leads to very serious learning difficulties in mathematics is those misconceptions students may have from previous inadequate teaching, informal thinking, or poor remembrance. Recognition of misconception and the origins that create them in the fields and at different levels of education, can improve learning.  Misunderstanding in this study is incomplete or incorrect interpretation of a concept that cause systematic errors in the performance. This study investigates the student’s understanding and misconception of negative numbers. Descriptive statistics, survey, is used as a method of this study. The population of the study is all second level students of guidance school in the academic year 1391-92 and all the seventh level students of Darmian town in the academic year 1392-93. 443 students in second level of guidance school and 55 students in seventh level were chosen as a sample of the study based on cluster random sampling. A self-designed questionnaire by the researcher is used as the instrument for the study, the questionnaire was based on “Bofferding” and “Kilhamn” questionnaire. Results showed that most of the students don’t have a true understanding of negative numbers in school and face problems in applying their knowledge to solve mathematical problems. Also the results of the current study showed that some of the students consider "-" as a reducing operator and some consider "+" as an increasing operator.