Mathematics learning in the high schools in the author's target area which includes SMA A, SMA B, SMA C, SMA D, SMA E, SMA F and SMA G, is experiencing problems that must be addressed immediately. This was identified from the low average UTS II results for the 2021/2022 school year. The percentage of completeness achieved by each school is very low, below 85% as the percentage of classical completeness that has been set. From the identification of the problem, it was found that learning was still dominated by the teacher. Learning takes place only by applying the lecture method without being accompanied by methods that can increase student engagement. Low student activity. The teacher never provides feedback to determine the achievement of learning objectives. The teacher also never held any follow-up to overcome learning problems, except for only holding remedial, without being accompanied by efforts to improve the learning design which was embodied in a classroom action research. So it is necessary to make efforts to increase the ability of teachers to carry out classroom research through structured guidance. The research design consisted of four stages, namely planning, action, observation, and reflection. The research consisted of two cycles. Each research cycle is always carried out in a collaborative participatory manner between researchers and colleagues. From the research results, it was concluded that there was an increase in the teacher's ability to carry out classroom action research. This is based on the results of observations of learning tools and learning observations on both the teacher and student aspects, as well as the physical evidence of the resulting research papers. Efforts to increase the ability to carry out classroom action research, begins with explaining the purpose and providing apperception. Furthermore, the teacher discussed the design of classroom action research. The teacher carries out classroom action research, according to the plan that has been prepared.