The existence of ethnomatematics has existed since long ago. This is seen from various mathematical concepts that have become part of the life and traditions of society. One of them is contained in tapis Lampung. Tapis Lampung has motifs and patterns that describe the philosophy of Lampung people. Each motif has meaning and symbol in the pattern of cultural life. The process of developing Tapis Lampung has had a major impact on the economy of the community and significantly increased the potential of cultural tourism in exploring the wealth of the Indonesian art heritage. This process of introducing culture in a mathematical perspective better known as ethnomatematics. This concept has become the basis of society in using mathematics in life. This study aims to examine the philosophy contained in motifs of tapis and analyze the mathematical concept to find an ethnomatematics approach in mathematics learning. in various types of tapis Lampung including: Tapis Cucuk Pinggir, Tapis Jung Sarat, Tapis Limar Sekebar. Mathematics concept include One-Dimentional Geometry and Two-Dimentional Geometry, Geometry Transformation includes: concepts of reflection, dilation and rotation.

[FORUM GUMEULIS: EFFORTS TO IMPROVE TEACHER COMPETENCE IN WRITING SCIENTIFIC PAPERS IN TASIKMALAYA CITY]. The purpose of this study is to describe efforts to improve teacher competency in writing scientific papers through the activities of the Gumeulis forum in the City of Tasikmalaya, through training, guidance, mentoring and hands-on practice. The research method used is qualitative research with a type of case study. Data collection techniques through interviews, observation, and study of documentation. The results showed: (1) improvement of teacher competency in the city of Tasikmalaya in making the scientific paper more effectively carried out through teacher writing forums. (2) the development of teacher professional competence in making scientific papers through the Gumeulis forum activities shows an increase in teacher competency. (3) through the Gumeulis forum, there is mutual interaction together to learn to make Eastern Indonesia. (4), the Gumeulis Forum can create a conducive academic climate in improving teacher competency in creating scientific papers. The conclusion of the research shows that by learning together in the community will be able to improve the competence of teachers in writing scientific papers. This is because among members can discuss and learn together. Under the guidance of senior teachers in the community.

Thematic learning is expected that learning activities can involve students actively and in learning activities, so that students get direct experience which makes learning activities much more meaningful. Thematic teaching materials with the STEM approach are an alternative to improve students' problem-solving abilities. This study aims to analyze the validity, convenience, attractiveness, usefulness, and effectiveness of thematic teaching materials with the STEM approach to improve students' problem solving abilities in elementary schools. This research is a type of Research and Development (R&D) research, the development is carried out according to the theory of Borg & Gall. The subjects in this study were determined using a purposive sampling technique and obtained as many as 20 students. The data collection tool uses valid and reliable test instruments. Validity data analysis techniques show that thematic teaching materials with the STEM approach are very valid to use. Effectiveness data analysis technique uses N-Gain with a calculation result of 0.57 with a significance of 0.01<0.05. Based on this research, it can be concluded that the thematic teaching materials with the STEM approach developed are valid and effective for improving students' problem solving abilities in elementary schools.

This type of research is development research that refers to the theory of Borg and Gall. The population of this study was all fifth grade students in SD Negeri Gugus I, Rajabasa Subdistrict and a sample of 51 students obtained by purpose sampling technique were students of class V B of SDN 1 Rajabasa as Experimental Classes and students of class V B SDN 3 Rajabasa as a control class. Data collection techniques use test results of learning and observation. The feasibility of the instrument is theoretically based on expert judgment with an average of 90.09 very good categories. While the feasibility of the instrument empirically based on the analysis 20 essay questions are worthy and quality from the results of the test of validity, reliability, different power, and level of difficulty. Mathematical textbooks based on realistic approaches are also effective. This can be seen from the average value of students in the experimental class using a realistic textbook based on mathematical approaches that is 74.29 higher than the average value of students in the control class who do not use mathematical textbooks based on realistic approaches, namely 59.47 with the normalized Gain value of 0.38 with the "medium" category.

This research and development aims to develop and describe the feasibility and effectiveness of mathematics student worksheet based on pictorial riddle model in improving students' critical thinking skills. The type of research used is research and development that refers to the theory of Borg and Gall. The population of this study was fourth grade students of Elementary Schools in Bangunrejo. The study sample was 32 fourth grade students of Tanjung Jaya Public Elementary School 1 which were determined by purposive sampling technique. Data was collected through questionnaire sheets, observation sheets and test questions. The results of the study showed that the student worksheet based on pictorial riddle model was feasible, and effective for improving students' critical thinking skills. Keywords: The development of student worksheets, pictorial riddle.