This study aims to develop android-based mathematics learning media on polynomial material that is valid, practical, and effective for use in learning. This type of research is research and development by applying a 4-D development model which has stages consisting of: define, design, develop, and disseminate. The data collection instruments used were an expert validation questionnaire, practicality questionnaire, and pretest-posttest questions. The subjects of this study were students of class XII SMAN Gogol. The results show that the assessments of material experts and media experts obtained valid criteria. In the practical aspect, the learning media are stated to be very practical to use as a support for learning from the assessment of teachers and students. In the pretest-posttest results of students, the increase in learning outcomes is at the "medium" level seen from the n-gain test scores so the "Pintar Polinomial" learning media is declared to be effectively used in learning polynomial material. It can be concluded that the "Pintar Polinomial" learning media is feasible to use in learning because it has met the criteria of validity, practicality, and effectiveness.

This study aimed to develop manipulative learning media based on STEM (Science, Technology, Engineering, and Mathematics) called Magic Hours on Clock and Corner material. Research and development model used by using the procedure of Analysis, Design, Development, Implementation, and Evaluation (ADDIE). The population of this study was all 4th grade students from elementary school in Kediri. Due to the Covid-19 Pandemic situation and study from home policy, manipulative media was tested on 13 fourth grade elementary school students in Kediri who came from the same village to reduce students' mobility from one place to another. Data collection techniques are collecting through expert validation, teacher questionnaires, student questionnaires, test, observation, and interviews. The instruments are test (description questions) and non-test instruments (material validation sheets, design validation sheets, practicality assessment sheets, questionnaire validation sheet, and questionnaires). The result shows that the learning media are valid, practical, and effective. Learning media have feasible criteria with an assessment score of 88.46% from media experts and 86.67% from material experts. In the practicality test, learning media obtained a percentage of 86.67% with practical criteria. The result of a one-sample t-test on student test scores indicates that the average mathematics score test is significantly more than Minimum Completeness Criteria.

This study aims to describe the process of developing interactive multimedia learning mathematics Lectora Inspire that satisfies criteria: valid, practical, and effective to reinforce the conceptual understanding of 8th graders of junior high school, especially on Linear Equation System in Two Variables (LESTV) topic. This research uses the Analysis, Design, Development, Implementation, and Evaluation (ADDIE) model. The result of media and content expert validation showed an average score of 84% and 83.5%, respectively, such that it met the valid criteria and without revision. The result of the student questionnaire said that the media was good with scores of 79% and the average point of the test was 86.5 of 100. It showed that the student concept understanding was complete after using the media. The media need to be improved before it was used broader.