This research is motivated by demands for mastery of 21st-century skills as a form of educational reform in the 4.0 era. This study aims to explore the understanding and skills of the prospective mathematic teacher in the development of the student e-worksheet as a form of teacher skills in the 21st-century. A total of 27 math teacher candidates in Banyumas Regency, Central Java, Indonesia, who took part in training teaching material development, was formed into 9 Groups (G) and was given the task to develop student e- worksheet of mathematics of junior high school. Data were collected through observation, interviews, self-reflection, open questionnaires, and portfolios and analyzed using content analysis procedures by reading carefully to understand relevant themes. The coding and labeling are then carried out to find the meanings associated with the research objectives and theoretical framework. This study's results indicate that self-regulated learning of prospective mathematics education teachers in the development of student e-worksheet can encourage motivation to learn, self-confidence, experience, and determination to become professional teachers in the 21st century. From this study, an understanding and skill of the century 21can be explored from self-regulated learning during the development of student e- worksheet, namely collaboration and communication skills, problem-solving, creativity and imagination, innovation, and novelty, literacy, and leadership.

The research aims to construct learning media for pop up books on cube and block materials that are suitable for use in junior high school students. This research is a development study using a modified 4-D model that is Define, Design, Develop and Deseminate from Thiagarajan. The subject of the material developed in this study was cube and beam class VIII material with a class VIII trial subject of SMPN 1 Sumbang. The results showed that the learning media pop up book was very valid (3.57) according to the validator, the teacher's response was very good (3.31) and student responses were good (3.29)

The mosque is the oldest Islamic culture which is the centre of civilization for Muslims for every group, both adults and children. However, so far the mosque environment is rarely used as an effective learning resource to explore more contextual, meaningful and educational mathematics material. The purpose of this study was to explore mathematics teaching materials and religious values from objects (artefacts) around the mosque. The artefacts explored are mosque objects that have religious values, namely prayer rugs, prayer rugs, mosque reliefs and covers of the Qur'anic manuscripts. The research location is in the Baitu Usyaqil Quran (BUQ) Mosque and the Pesantren Darussalam Purwokerto Mosque, Banyumas, Central Java. The data collection method uses observation, documents and a literature review. The data analysis technique used descriptive qualitative analysis. The results showed that, prayer rugs, prayer rugs, mosque reliefs and covers of the Qur'anic manuscripts contain various transformational geometry concepts such as symmetry, reflection, translation, rotation, and dilation. The results of this study are very important for developing a mathematics curriculum based on student culture.

The purpose of this study was to express spiritual values in mathematic learning of Relations. This study was a qualitative research with a case study method with a grounded theory approach. The research subjects were mathematics teachers and 2ndstudents of MTs 1 Banyumas who were selected using purposive sampling technique. Methods of data collection through in-depth interviews, observation, and document studies. Data were analysed with inductive method and discribed with narative. The results showed that the spiritual values in relation material can be extracted from the ontological concept of relations. Spiritual values in Relationships philosophically contribute to the development of the structure of human life

Based on RISKESDAS data for 2018, 57.6% of people in Indonesia have dental and oral health problems. Meanwhile, in the province of Central Java, dental and oral health problems reached 56.66% and only 9.02% received treatment. In the city of Semarang, dental and oral health problems reached 48.38% and only 14.22% received treatment. Dental health problems in adolescents are not much different from dental and oral health problems in children and adults. There are many ways that can be done to overcome these problems including the use of multimedia as an educational medium. The use of Augmented Reality has proven effective in increasing student learning interest. Proving the effectiveness of applying the CAKAR model (Augmented Reality Tartar Disc) as an educational medium in increasing changes in adolescent behavior in preventing tartar. The method used is Research and Development with a Quasy experiment Pretest-Posttest group design research design. The "CAKAR" model is appropriate as a media for dental health education with expert validation results of 82% and a p-value of 0.008, as well as the results of the delta test stating that its application is effective in increasing intervention knowledge (Δ5.03), control (Δ0.63), intervention attitude (Δ6.9). ) control (Δ0.16), intervention measures (Δ2.63) control (Δ0.43), and decreased OHIS intervention score (Δ0.42) control (Δ0.18). The application of "CAKAR" is appropriate and effective in changing adolescent behavior in preventing tartar.