The investigation of two beginning middle school mathematics teachers' professional development within the framework of five practices

The purpose of this study was to investigate the effect of a professional development program based on 5 Practices to the clasroom routines and cognitive demands of mathematical tasks implemented by two beginning middle school mathematics teachers. For this purpose, the study was carried out in two phases: Before the professional development program and theoretical and practical phases of professional development program. Because of the fact that this study was designed as a case study, qualitative data collection and analysis methods were utilized. The findings before the professional development program suggested that teachers did not perform a planning based on student thinking, didn't provide enough time for students to explore the tasks, didn't create an environment based on classroom discussions and they usually implemented cognitively low-demanding mathematical tasks. Along with the professional development program teachers deeply considered on the purpose of cognitively demanding tasks they planned, but did not reach the expected level on detailed anticipating. They constructed an environment based on students' exploration of tasks and consideration of different solutions. They purposefully selected and sequenced different solutions. In particular, they were able to initiate discussions to connect students' approaches and underlying concepts, but they did not reach the expected level in making connections among different solutions. Teachers mostly maintained the level of cognitively high demanding tasks in the professional development program. Keywords: Beginning teachers, Professional development, Mathematical tasks, Cognitive demand, 5 practices.