Mistake Handling Activities in the Development of Middle School Mathemathics Teachers’ Subject Matter Knowledge: Addition Operation with Fractions

In this study, the effects of mistake handling actvities in the development process of middle school mathematic teachers’ subject matter knowledge for addition operation with fractions was examined. For this purpose, teachers’ subject matter knowledge in the context of operation, problem posing, using model, explain and know important points about addition operation with fractions set before applications supported by mistake handling activities. Case study methods from qualitative research approaches was used as the design of study, where seven middle school mathemathics teachers were sampled. Teachers were selected by using purposive sampling technique. Datas were obtained through subject matter knowledge test, focus group inteviews and diaries. Descriptive analysis was applied to the collected data. According to the results of the study, it was seen that problem posing skills of teachers were lacking in the context of subject matter knowledge