The present research is a qualitative study using elementary teachers’ reflective practices. The study will be conducted with two elementary teachers in one private elementary school in Ankara. Two mathematics programs, namely Primary Years Math Program (PYP-math) and mathematics program designed by Ministry of National Education (MoNE) have been integrated in this school in 2010.There are approximately 100 staff including coordinator, principle and vice principals, teachers, counselors, program development expert, and measurement and evaluation expert in this school. The school has approximately 700 students from kindergarten to 8th grade. There are four sections at each grade level. The school starts at 8.30 in the morning and finishes at 15.35 and teachers are to be at school during whole week between these hours except for one half day in a week. In addition to these, for Tuesdays and Thursdays the working time extends to 17.00 and all the meetings and workshops are planned in this period.The school is implementing a new program for two years for K5 grades. This program is called Primary Years Program (PYP), which is a part of International Baccalaureate Program (IB) developed by International Baccalaureate Organization (IBO). The International Baccalaureate Organization (IBO) was established in 1968 and is a non-profit, international educational foundation registered in Switzerland. The PYP is based on the inquiry and thematic in nature. Teachers teaching the same grade level come together and develop six transdisciplinary thematic units to be covered during whole year.