Mathematical reasoning in logical context has now received much attention in the mathematics curriculum documents of many countries, including Indonesia. In Indonesia, students start formally learning about logic when they pursue to senior-high school. Before, they previously have many experiences to deal with logic, but the earlier assignments do not label them as logic. Although the students have already experienced much about logic, it does not assure that they have a better understand about it even they purpose to university. Thus, this paper presents several findings of our small-scale study which was conducted to investigate the issues on how higher-education students overcome contextual logic-based problems. Data were collected through pretest, students' written work, video recording and interview. A fifteen-minute test which consisted of four questions was given to 53 student participants in the third semester who proposed mathematics discrete course. The information towards the main issues was required through the analysis of students' written work in the pretest and video recording during the students' interview. The findings indicate that the students' initial understanding, in general, do not help them much to solve logical problems based on context. In our findings, they apply several strategies, such as random proportions, word descriptions, permutation-combination calculations and deriving conclusion through logical premises.

Kemampuan visualisasi memiliki peran penting dalam pengembangan pemikiran matematis yang berkaitan dengan pemecahan masalah matematika pada topik bangun ruang. Dengan adanya kemampuan visualisasi yang baik siswa dapat menginterpretasikan bentuk-bentuk bangun ruang tersebut sesuai dengan permasalahan yang diberikan. Beberapa penelitian sebelumnya (Syahputra, 2013; Kariadinata, 2010; Isnaini, 2017) yang mengatakan bahwa siswa masih mengalami kesulitan dalam memahami objek atau gambar bangun ruang 3D. Penelitian ini bertujuan untuk mendiskripsikan adanya pengaruh media pembelajaran HOLO-MATH (Hologram Mathematics) dalam meningkatkan kemampuan visual matematis siswa di SMP Negeri 8 Percut Sei Tuan. Dalam penelitian ini penulis menjelaskan secara deskriptif tentang pengaruh hasil belajar siswa. Penelitian ini dilakukan di kelas VIII yang terdiri dari 27 orang siswa. Metode yang digunakan pada penelitian ini adalah Research and Development dengan model ADDIE. Pengumpulan data diperoleh dengan Data Triangulation. Hasil dari penelitian ini yaitu terlihat adanya peningkatan dari hasil belajar siswa setelah belajar dengan menggunakan media pembelajaran HOLO-MATH. Hal tersebut dapat ditunjukkan dari perbandingan hasil pre-test dan post-test siswa yang mengalami peningkatan dari hasil sebelumnya dengan persentase N-Gain sebesar 32,9%. Melalui proses pengerjaan jawaban siswa, terlihat juga kemampuan visual matematis yang meningkat. Dengan demikian terjadi pengaruh yang signifikan dalam meningkatkan kemampuan visual matematis siswa ketika menggunakan media pembelajaran HOLO-MATH. [Penerapan Media Pembelajaran Holo-Math (Hologram Mathematics) Dalam Meningkatkan Kemampuan Visual Matematis Siswa Di SMP Negeri 8 Percut Sei Tuan

This research was conducted with the aim of describing the initial mathematical reasoning ability level of junior high school students on the topic of Cartesian coordinates. This research uses descriptive qualitative method. The subjects in this study were 38 grade VIII students of SMP IT Al Hijrah Medan. The research instrument used was in the form of four questions worked on by students with a duration of 60 minutes. Data collection techniques in this study are through observation, interviews, and documentation. Documentation plays an important role in this research because it describes how the research process takes place. The research began with the observation stage, and continued with taking tests of students' mathematical reasoning abilities, then the researchers conducted interviews with students regarding student test results. The results showed that the students' initial mathematical reasoning abilities were still at a low level. In this case, the researcher found that students' initial reasoning abilities had not been able to help students in solving problems.

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The industrial revolution 4.0 requires human resources who can design and make innovation in various fields including education. The design and innovation cannot be separated from the role of research. DBR as one of the research methodologies is a bridge between the innovations that are developed with the practice in formal education. Validation in a real context provides certainty that the research design can be used effectively to assess, inform, and improve activity at least in that context. However, many university student have not used DBR in educational research. The results of the questionnaire and interviews showed that many mathematics education students have no prior experience about DBR. In fact, as prospective educators, they should know DBR as a provision in designing innovative learning in for their future career. Therefore, this study aims to describe our step in course about how to support students to understand and be skilled in applying DBR. By emphasizing the student centred learning combined with context-based problems, we have succeeded in guiding students starting from strengthening DBR theory, designing learning that is appropriate to the student context, applying its design in the classroom, and finally, students can produce a valid and innovative learning design.