Learning in the industrial revolution 4.0 requires the optimal use of technology in the learning, one of which is by learning to use mathematical e-modules that can be operated on smartphones using an android operating system. This study aimed to create valid, practical, and effective android-based e-modules. This research was research and development (R&D) with the Plomp development model, which consists of the preliminary research phase, the development or prototyping phase, and the assessment phase. The subjects of this study were students of grade X in SMA N 5 Pekanbaru. The results of this study were the android-based e-module was valid, practical, and effective. The validity of e-modules was classified based on the results of the experts' evaluation. The practicality of the e-module was classified based on the questionnaire responses of teachers and students, who can use the e-module well, can help students in understanding the material, and interested in using it. The effectiveness of e-modules was classified by the percentage of student's completeness learning after using e-modules more than 70%.

The mathematical ability of Indonesian students is still very low compared to other countries. One alternative to overcome the problem is by creating learning instructional that allows students to learn well. Most of learning instructional developed today do not accommodate the student learning styles especially in schools that have classified students based on multiple intelligences. The dominant intelligences in the classroom are intrapersonal and interpersonal. The purpose of this research is to produce a mathematics learning instructional based on Discovery Learning approach that are valid, practical, and effective for junior high school students with intrapersonal and interpersonal intelligence. These instructional are developed using a development model adapted from the Plomp model. The development process of these instructional consists of 3 phases: front-end analysis/preliminary research, development/prototype phase and assessment phase. From the preliminary research results, we obtain that the intrapersonal student learning outcomes are not different from interpersonal. Teachers and students desperately need learning instructional with simple language and can guide students to understand the subject matter.

This study aimed to improve students’ achievement in elementary linear algebra through APOS theory approach. This study is pre-experimental one-shot case study design. The sample were 32 students who participating in the lecture of chemistry mathematics II academic year 2018/2019 at Andalas University. Instrument used in this study was problem solving test in elementary linear algebra which consisted of four item test that measures the ability to solve daily life problem with system of linear equation, determine determinant of the matrix, determine invers of matrix, and determine eigen value and eigen vector of matrix. Descriptive statistics and t-test with α = 0.05 level of significance were used for data analysis. The results show that: (1) APOS theory approach can improve students’ achievement in elementary linear algebra significantly and (2) there was no a significant gender gap in students’ achievement in elementary linear algebra.

This study aimed to develop a learning trajectory (LT) for teaching sets using Realistic Mathematics Education (RME) approach and to investigate its influence on student ability. The LT was developed through a design research which consisted of a cyclic process of preparing for the experiment, conducting the experiment, and retrospective analysis. The subject of the study was students at grade VII in Padang. Data were collected through direct observation, interview, and check list, videotaping, and analyzing the work of the students. The LT was evaluated through one-to-one and small group evaluation before it be tried out in a test. The whole strategy (emergent modeling) showed the construction and contribution of the students in discovering the concept of sets from the informal to the formal level. It could help the students to reinvent sets concept. Finally, we discovered that the students increased their mathematics creative thinking ability.

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