The purpose of this article was to find out the enhancement of students' mathematical problem solving by using visual learning media. The ability to solve mathematical problems is the ability possessed by students to solve problems encountered, one of the problem-solving model of Polya. This preliminary study was not to make a model, but it only took a conceptual approach by comparing the various literature of problem-solving skills by linking visual learning media. The results of the study indicated that the use of learning media had not been appropriated so that the ability to solve mathematical problems was not optimal. The inappropriateness of media use was due to the instructional media that was not adapted to the characteristics of the learners. Suggestions that can be given is the need to develop visual media to increase the ability to solve problems.

The development of learning models based on integrated STEM lower secondary education projects has not yet been carried out. The integration of STEM into education is necessary because the high demand for human resources in 21st century STEM mastery-based learning provides space for students to choose activities to be carried out during learning, it also presents great opportunities for teachers to observe activity in developing student abilities. Quantitatively, an integrated project-based STEM learning model can improve students' critical thinking skills in mathematics in junior high school. In this regard, this study aims to develop project-based teaching materials that present mathematical topics combined with other STEM field teachers. The research method used is research and development. In this study only carried out at the stage of testing the validity of teaching materials that have been developed. Data collected during the study are material content validity evaluation sheets, advance validity, and construct validity, as well as conclusions on the feasibility of teaching materials. The data obtained were tested using Q-Cochran. The results showed that the integrated Project-Based Learning STEM teaching materials had passed the pace of development, an examination by judicial experts, and expert media testing to validate teaching materials. The validation results show that the face validity and the content validity of the teaching materials are valid and feasible. Then the results of construct validity are included in the validity of very good to very good. Then the validity of each item on the evaluation shows the high validity of the dominant values. It can be concluded from this study that the teaching materials developed have high flexibility, the instructions contained in the teaching materials are easily understood by students, and are suitable for use in a limited scope.

This study aims to determine the process of developing android-based learning media on comparative material to improve mathematical problem-solving skills and find validation through android-based learning media to improve mathematical problem-solving abilities. This research was conducted through research and development, where this research refers to 4D development, which consists of four steps: define, design, develop, and disseminate. This research was carried out to develop measures due to restrictions on the activities of emergency communities affected by the COVID-19 pandemic; this is one of the limitations of this research. Researchers use documents such as curriculum to collect data at the define and design stages, while a validation sheet is used for the development stage. The data analysis technique used descriptive qualitative at the define and design stage, and the development stage uses quantitative descriptive analysis. The main finding in this research is the prototype of android learning media on ratio. The results showed that V Aiken obtained more than 0.750, so this media prototype can be used for the following research stage.

The purpose of this research is to find out the students' thinking process in formal cognitive development in solving mathematical problems. The problem solving used in this study uses patterns from the pattern that have been adapting to the habits of students in Indonesia, namely the first stage is known, the second stage is asking, and the third stage is answering. This study was included in a qualitative descriptive study using six junior high school students with formal that were used as research subjects. The research instrument used in this study is Test of Logical Operations and mathematical problem-solving tests. Data analysis techniques are used using Milles, Huberman, and Sandana. From the results and discussion of the research carried out, it can be concluded that students with formal cognitive in the first and second stages tend to think about assimilation and abstraction. While in the third stage, students in formal tend to think about assimilation processes even though there are subjects who do the accommodation thinking process.

The purpose of this study was to determine the relationship between the level of anxiety and learning motivation on student achievement. This research is a kind of ex post facto, a six-month study period. A population of 125 students, with a sample of 100 students were randomly selected. The research variables are student achievement as the dependent variable, while the independent variable is the level of anxiety of students and student learning motivation. Data collection methods used were the questionnaire method and documentation. Data analysis technique used is path analysis. It can be concluded that there is a negative relationship between anxiety level of students' motivation, there is no direct relationship between the level of anxiety of students on student achievement through student learning motivation, there is a positive relationship between learning motivation on student achievement. So it can be stated that there is a correlation between the level of anxiety and learning motivation of students simultaneously on student achievement.

The purpose of this paper is to know the effectiveness of teaching materials algebraic equation. This type of research used experimental method. The population in this study is all students of mathematics education who take numerical method in sarjanawiyata tamansiswa of university; the sample is taken using cluster random sampling. Instrument used in this research is test and questionnaire. The test is used to know the problem solving ability and achievement, while the questionnaire is used to know the student's response on the teaching materials. Data Analysis technique of quantitative used Wilcoxon test, while the qualitative data used grounded theory. Based on the results of the test can be concluded that the development of teaching materials can improve the ability to solve problems and achievement.