This paper reports some results of a research attempted to cultivate students' mathematical reasoning ability (MRA) by means of implementing problem-based learning (PBL) model. The population was upper secondary students of public schools in Bandung. Cluster sampling technique applied to take sample of amount 158 students from middle-level schools. Data were teacher's assessment on students' performance in last two months, prior mathematical knowledge (PMK) and MRA test, observations, and interview. Two-factors ANOVA then used to analyze the data. Findings showed that overall students in PBL-classroom achieved better MRA than their counterparts in conventional one though the category in both classrooms was low. Interaction between PBL and PMK factor towards MRA did not emerge. Most part of the participants viewed PBL neither positive nor negative. On the contrary, they assessed that the tasks given made and demanded them thinking and learning more actively than ever. The findings showed adopting PBL in schools to facilitate students getting their higher order thinking skills is a reasonable choice, especially schools having middle or high ability students.

The present study aims at examining the use of open-ended approach in cultivating senior high school students' mathematical creative thinking ability (MCTA) and self-esteem (SE) in mathematics viewed from school category. The subjects of this research were the students grade XI at three schools; a high, middle and low group in Kota Serang, Banten Province. In every school category, two classes were chosen; one class was the experimental group which was taught by the open-ended approach, while another class was a control group which was shown by conventional way. This quasi-experimental research employed MCTA test and SE in mathematics scale as the instruments. In general, the research result shows that the MCTA improvement and SE level of the students who are taught by open-ended approach are better than those who are taught conventionally. The results of students' MCTA and SE viewed from school category will be further discussed. Keywords: mathematical creative thinking ability, self-esteem, open-ended approach AbstrakPenelitian ini bertujuan untuk mengkaji pendekatan open-ended untuk meningkatkan kemampuan berpikir kreatif matematis (KBKM) dan self-esteem (SE) dalam matematika pada siswa SMA ditinjau dari ketagori sekolah. Subjek penelitian ini adalah siswa kelas XI pada tiga sekolah dengan kategori sekolah tinggi, sedang dan rendah di Kota Serang Provinsi Banten. Pada tiap kategori sekolah dipilih dua kelas, satu kelas menjadi kelas eksperimen yang menerapkan pendekatan open-ended, dan satu kelas lainnya sebagai kelas kontrol yang menerapkan pendekatan biasa. Instrumen penelitian kuasi eksperimen ini adalah tes KBKM dan skala SE. Hasil penelitian secara umum menunjukkan peningkatan KBKM dan pencapaian SE siswa yang mendapatkan pembelajaran open-ended lebih baik dari pembelajaran biasa. Disajikan juga pembahasan mengenai peningkatan KBKM dan pencapaian SE siswa tersebut ditinjau dari tiap kategori sekolah.Kata Kunci: kemampuan berpikir kreatif matematis, self-esteem, pendekatan open-ended

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<p>Penelitian ini dilatarbelakangi oleh rendahnya kemampuan penalaran matematis siswa SMP pada materi geometri. Metode penelitian yang digunakan adalah penelitian desain didaktis (<em>didactial</em> <em>design research</em>).  Penelitian diawali dengan studi pendahuluan untuk mendapatkan data kesulitan belajar (<em>learning obstacle</em>) yang dilaksanakan di SMP Negeri 29 Bandung kelas IXE sebanyak 35 orang, SMA Negeri 1 Lembang kelas XI IPA2 sebanyak 41 orang, dan STKIP Siliwangi Bandung mahasiswa semester VI sebanyak 49 orang pada tahun pelajaran 2011/2012 semester genap. Selanjutnya, dikembangkan desain didaktis yang diujicobakan terbatas kepada 30 siswa kelas VIII B SMP Assalam Bandung. Dari uji coba terbatas dilakukan analisis untuk menyusun desain didaktis revisi. Hasil dari penelitian ini diantaranya perangkat pembelajaran yang digunakan pada pembelajaran sebelum menggunakan desain didaktis belum dapat menggali kemampuan penalaran matematis, desain didaktis penalaran matematis yang dikembangkan dapat memperkecil <em>gap</em> yang dihadapi siswa, dan siswa memberikan tanggapan positif terhadap desain didaktis yang dikembangkan.<strong></strong></p><p>The background of this research was the lack of junior high school students’ mathematical reasoning in geometry. This research used Didactical Design Research (DDR) method which started by a preliminary study to 35 students of grade IX E Public Junior High School 29 Bandung, 41 students of grade XI Science Program of Senior High School 1 Lembang, and 49 students of Siliwangi College of Education Bandung in semester VI for academic year 2011/2012. The preliminary study was aimed to explore students’ learning obstacles to develep didactical design. The developed didactical design was implemented to 30 students of grade VII B of Assalam Junior High School Bandung. After this implementation the developed didactical design was revised. The results of this research were the learning tools used by previous teacher have not explored mathematical reasoning yet, the developed didactical design had minimized students’ gaps, and students had positive response about the learning.</p>

This study is a series of Didactical Design Research in prospective analysis stage to comprehensively identify some obstacles in learning negative integer in order to capture how the learning process used by teachers and how the impact on students in understanding the concept of negative numbers. This research is a case study administered to seventh-grade students in one of the classes in a junior secondary school in Indonesia to investigate how the teacher managed the learning process of integers and identify students' thinking construction. Involving a mathematics teacher and 37 students, this qualitative study collected data from field observations, interviews and document review. The data were analyzed by the perspectives of learning obstacles based on Theory of Didactical Situation. Findings show how teacher describes the negative integers and the arithmetic concepts to the students and its contribution in causing misunderstanding on the students. Within the framework of epistemological obstacles, the result of this study is used as a basis for designing a learning program which can overcome problems related to teaching and learning of negative integers.

This paper reports the findings of a quasi-experiment that aims to investigate the role of metacognitive teaching-learning (MTL) and mathematical prior knowledge (MPK) on students' mathematical logical thinking ability (MLTA) and selfregulated learning (SRL). The subject of the study was 70 tenth-grade students inSumedang, Indonesia. One experimental group and one control group were used, and the students were grouped into three categories based on their mathematical prior knowledge (high, medium and low). The instruments of this study were a short-answer-MPK test, an essay MLTA test, and a SRL scale. The data were analyzed by using Anova, t-test, Mann-Whitney test, and Kruskal-Wallis test. The study find that compared to conventional learning, MTL gave better influence on students with medium MPK in MLTA and gave an overall better effect on students in SRL. However, for entirely students, the students' grades of SRL are fairly good, but the students' grades of MLTA are still low. There is no interaction between learning approaches and MPK on improving MLTA, and there is an interaction between learning approaches and MPK on improving SRL.

This study revealed how students' understanding of negative numbers and identified their difficulties related with the concept of integer and its counting operation as part of identifying epistemological obstacles about negative numbers. Even though teachers have explained counting operation procedure of integer, but there was concept misunderstanding among students. The concept difference between what was comprehended by respondents in their learning process and knowledge science has resulted in wrong perceptions about the negative numbers. In this article, the authors explained how these misunderstanding in concepts occurred among students and how these ideas were expressed by the students in solving the problem which was related with counting operation of negative integer. This study was part of Didactical Design Research using qualitative approach in negative number learning by involving 96 students of 7th grade as participants in three different schools. This study showed some difficulties by the student to understanding negative numbers in terms of prerequisite knowledge, understanding concepts, procedures, principles and problem solving.

The purpose of this research is to analyze the level of abstraction mathematical ability of the students through learning using Realistic Mathematics Education (RME) with Visual Basic Application (VBA) for Microsoft Excel. This research uses a descriptive qualitative method and the subject of this study is junior high school students of grade 9th in one school in Ngamprah as many as 35 students. One of the instruments in this study is the abstraction test. Results show that as many as 65.71% of students are in the first level of Perceptual Abstraction. As many as 57.14% of students are in the second level of Internalization.  As many as 31.43% of students are in the third level of Interiorization, and as many as 17.14% of students are at the last level, namely Second Level of Interiorization. Overall, the sample in this study can be categorized into four levels of abstraction.