On Wednesday, July 30, 2025, a training and workshop for junior high school mathematics teachers in Wonosobo Regency was held at SMP N 1 Kepil Wonosobo, initiated by the PkM KBK Teacher Professional Development team consisting of Tuharto M.Si, Dr. R. Rosnawati M.Si, Caturiyati M.Si, Prof. Dr. Ariyadi Wijaya, M.Sc., and Ilham Rizkianto, M.Sc. The activity was held from 8:30 a.m. to 3:00 p.m.. It was attended by 28 junior high school mathematics teachers from 21 junior high schools and six junior high school principals in Wonosobo Regency. The Community Service Program, entitled "Improving the Professionalism of Mathematics Teachers through Guided Discovery-Based Mathematics Lesson Study in Wonosobo Regency," was conducted in collaboration with the Mathematics Teacher Working Group (MGMP) Working Group 3 (covering the subdistricts of Sapuran, Kepil, and Kalibawang, Wonosobo Regency, Central Java).

The objective of this PkM was to improve the competence of junior high school mathematics teachers through training in the application of lesson study, including: lesson planning conducted through focus group discussions (FGD) to design mathematics lessons for grade VII on the topic of flat-sided shapes; open classes, which are lessons taught by model teachers and attended by other junior high school mathematics teachers; and reflection on the results of lesson observation to improve lesson design. Lesson study can be considered a cycle of learning improvement because it involves teachers in active learning about content, is driven by data and goals, and is continuous, intensive, collaborative, and practice-based, making various types of knowledge more visible. Through lesson study, teachers can learn about the design and implementation of discovery learning, which is expected to provide an in-depth understanding and develop active learning methods by discovering and investigating for themselves, so that the results obtained will be retained in their memory for a long time.

The training was conducted over four days. The first two days were conducted online to design learning tools (plans) with focus group discussions (FGD) to understand the effectiveness of discovery learning designs and the learning process that occurs, both in terms of the breadth and trajectory of learning, as well as the design of activities based on the principles of the discovery process and the obstacles encountered when conducting guided discovery learning.

On the third day, an open class (do) was held offline at SMP N 1 Kepil Wonosobo, attended by 28 junior high school mathematics teachers and six school principals from 3 sub-districts in the South Wonosobo region. The model teacher was Ismul Farikhah, S.Pd.Si from SMP Negeri Sapuran 1. The activity was one of the stages of lesson study, namely, reflection on what had been done during the learning process. Mr. Tuharto, M.Si. and Mrs. Dr. R. Rosnawati, M.Si. guided the reflection activity. The participants enthusiastically shared their observations and suggestions for improvement in future learning activities.

The results of this reflection became input for all teachers in preparing a guided discovery learning plan, which is expected to provide an in-depth understanding and develop active learning methods by discovering and investigating for themselves, so that the results obtained will be long-lasting in their memory. This is in line with the independent curriculum, which supports in-depth learning. As a follow-up to the day's activities, participants were given an independent assignment titled "Development of Teaching Module Design," due two weeks after the activity. They will receive feedback and suggestions from the PkM team. (Caturiyati/HnR)