AbstrakPenelitian ini bertujuan untuk mendeskripsikan implementasi model problem based learning untuk meningkatkan kemampuan berpikir kritis mahasiswa pada mata kuliah Matematika Ekonomi semester V B tahun akademik 2015/2016. Jenis penelitian yang digunakan dalam penelitian ini adalah PTK melalui kegiatan Lesson Study yang terdiri dari tiga tahapan, yaitu perencanaan (Plan), pelaksanaan (Do) dan refleksi (See). Teknik pengumpulan data yang digunakan adalah tes, angket, observasi, catatan lapangan dan dokumentasi. Teknik analisis data yang digunakan adalah deskriptif kualitatif. Hasil penelitian menunjukkan bahwa klasifikasi kemampuan berpikir kritis mahasiswa pada open class pertama dan kedua tergolong cukup baik dengan persentase 67,33% dan 68,56%. Pada open class ketiga dan keempat, kemampuan berpikir kritis mahasiswa mengalami peningkatan dengan persentase 74,22% dan 77,78% dengan klasifikasi berpikir kritis baik. Oleh karena itu, kemampuan berpikir kritis mahasiswa pada mata kuliah Matematika Ekonomi dapat ditingkatkan dengan menggunakan problem based learning melalui kegiatan lesson study. Kata Kunci: Problem Based Learning, kemampuan berpikir kritis, Lesson Study AbstractThis study aims to describe the implementation of problem based learning model to improve critical thinking skills of students in the subjects of Mathematics of Economics V semester of the academic year 2015/2016. This type of research used in this study is the Classroom Action Research (CAR through Lesson Study activities which consists of three stages; plang, do and see. Data collection techniques used are tests, questionnaires, observation, field notes and documentation. The data analysis technique used is descriptive qualitative. The results showed that the classification of critical thinking skills of students in the first and second open class is quite good with a percentage of 67.33% and 68.56%. In the third and fourth open class, critical thinking abilities of students has increased with the percentage of 74.22% and 77.78% with the classification of critical thinking is good. Therefore, the critical thinking skills of students in the subject of Mathematics of Economics can be improved by using problem-based learning through lesson study. Keywords: Problem Based Learning, critical thinking skills, Lesson Study PENDAHULUANBerbagai upaya telah dilakukan oleh Pemerintah untuk mewujudkan pembangunan di bidang pendidikan seperti merumuskan berbagai pilar pembangunan pendidikan, pemerataan akses, peningkatan mutu, akuntablitas dan relevansi. Khusus pada aspek peningkatan mutu pendidikan, melalui Departemen Pendidikan Nasional telah dilaksanakan berbagai bentuk

Sasak traditional architecture, including the shape of the structure, layout, and other supporting buildings, has references and rules in its designing and planning. Traditional residence is one of the cultural artifacts. A residence is not only built based on aesthetic values, but is also reviewed from strengths and values contained philosophically. Thus, this study aimed to describe mathematical ideas that are contained in the architecture of Sasak traditional residence as well as educational values in the culture that can be made as the initial step in designing learning processes at schools. This study was qualitative research conducted by using an ethnographic method. The informants in the study encompassed <em>Adat</em> figures, <em>Adat</em> stakeholders, and cultural experts who understand the culture of Sasak people. Participant observation, interview, documentation, and field record were the data collecting techniques used in the study. Findings showed the existence of mathematical ideas that are potential to be made as the initial step in learning mathematics contextually.

This cultural diversity can be utilized in exploring mathematical concepts bridged by ethnomathematics to bring mathematics closer to students' cultures. However, on the other hand, many people think that mathematics is culture-free. The uniqueness and diversity of cultures in ideas, activities, and artifacts can be studied and used as learning resources, especially in mathematics. Therefore, this study seeks to explore the geometrical perceptions and cultural values contained in the traditional woven fabric motifs of the Sasak people. This research is qualitative research with an ethnographic method. Research data were collected through observation, literature study, and interviews with cultural practitioners, traditional leaders, woven fabric craftsmen, and cultural. The results of this study indicate that the traditional woven fabrics of the Sasak people have recognized and used mathematical concepts, especially lines, angles, flat shapes, and geometric transformations, in the design of traditional woven fabric motifs of the Sasak people. In addition, there is a philosophical meaning contained in each motif or pattern. The meaning is in the form of cultural values such as moral, historical, and philosophical values, which are used as messages to their children and grandchildren.

Perisean art developed since the 13th century according to existing history, which started with a ritual to ask for rain when there was a long dry season which resulted in a famine. Perisean art performances are currently used as mere agility art performances. Pepadu is a term for players or fighters. The show is led by three referees, one pekembar tengaq (middle referee) who is in charge of leading the fight and two pekembar sedi (side referee) who is in charge of determining each pepadu. Perisean art is not only studied in the form of art but can also be studied as a form of contextual learning in mathematics. Thus, this study aims to explore the forms of mathematics and cultural values contained in the performing arts of perisean which can later be used as a source of contextual mathematics learning. This research is a qualitative research using ethnographic method. The informants used are traditional figures, pepadu, and cultural experts who understand the art of perisean , documentation and field notes. The findings show that in the performing arts of perisean in the tradition of the Sasak people there are mathematical ideas, namely geometric shapes found in perisean art instruments and musical instruments. which has the potential as a starting point in contextual mathematics learning.

Mathematics is found in many activities of traditional culture. However, many perceive that mathematics is culture-free. Based on the occurring phenomenon, ethnomathematics study is made as the connector between mathematics and culture. The presence of ethnomathematics provides many opportunities to discover unique mathematical ideas exist in the traditional culture. This research aims to explore mathematical ideas in the layout of tui gubuk and the architecture of Segenter traditional house that can be made as mathematics learning sources. This study was a qualitative research with ethnographic method. This study was conducted in the traditional village of Segenter, Sukadana Village, Bayan District. Data were collected through an observation and interviews with Adat figures, cultural anthropologists, and traditional leaders who have the knowledge of the customs and culture of Bayan people, which consisted of three informants. Research results indicate that there are mathematical ideas in the layout of tui gubuk and the architecture of Segenter traditional house that can be made as the learning sources of mathematics and can be developed in mathematics learning, especially in materials of set and geometry, both geometry of space and flat geometry.