The purpose of this study was to determine the teachers’ practices and the difficulties encountered by the teachers in 5th grade optional ‘mathematics applications’ course, which came into effect with the new 4+4+4 educational system. The study was conducted in 2012-2013 academic year using the qualitative research method of semi-structured interview with 8 mathematics teachers who were teaching this course. The teachers were from four schools situated in socioeconomically average quarters of Eskişehir. The interview consisted of questions under three categories; aims and contents of the course, teachers’ practices and assessment of the course.