ETHNOMATHEMATICS VALUES IN SUMEDANG TOFU AND BONGSANG (TOFU BASKET) FOR TEACHING GEOMETRY IN PRIMARY SCHOOL

Ethnomathematics can be an option for teaching a more contextual mathematics which contributes to a successful mathematics learning. The present study highlighted ethnomathematics concepts that could be found in Sumedang’s local food, namely Sumedang Tofu, and the bamboo basket used as its container ( bongsang ). Mathematical concepts in Sumedang Tofu and its bongsang are related to geometry. Geometry allows students to develop their abilities in presenting or describing the order in the world or their immediate environment. Geometry learning affects students’ ability to connect mathematical ideas, both in the discipline and to other disciplines as well as the real world. The results of this study show that Primary School students still had difficulties in learning and understanding geometry. Therefore, it was necessary to develop a method that would improve students’ understanding of geometrical concepts, which were important because they were highly relevant to students’ daily life. The present study aimed t o explore geometrical concepts found in Sumedang tofu and bongsang . Descriptive qualitative approach was implemented, in which the data was gathered through observation, literature study, and interviews. The findings indicated that geometrical concepts could be found in Sumedang tofu and bongsang . Those concepts could be used in mathematics lessons in primary school to provide meaningful learning for students. The results of this study could be used as a foundation to develop an ethnomathematics learning in primary school level.


INTRODUCTION
Indonesia is a culturally rich nation whose people have strong characters.Local cultures are the root of Indonesia's national cultural diversity and contain positive values.Hence, it is important that local cultures are maintained and conserved.Moreover, the rapid spread of information technology and globalization has negatively affected the values of Indonesian culture.Massive influx of foreign cultures to Indonesia is threatening local cultures deeply embedded in daily life of Indonesian people, as evident in the trend that young people adores other countries' culture more than they do their own culture.
At the same time, in the result of the 2018 Programme for international Student Assesment (PISA), Indonesia ranked 74 th or in the bottom six.Specifically for Mathematics, Indonesian students scored 379, placing them in the 73 rd position.There are many factors contributing to the low performance in mathematics, including the implementation of mathematics learning that focuses more on transmission of knowledge.In other words, teachers did not provide enough practice (doing math) in lessons and students only passively received the material or lecture (Yuniawatika, 2011).
Mathematics is inseparable from human activities.It plays a great role in human advancement.Hence, it is taught in every level of education, including in primary schools.It is closely related to cultural development.Mathematics as a human activity is shaped and affected by local culture and values.As a discipline, mathematics can be used as a means to conserve and preserve culture in both local and national levels.
Considering that local cultures are dwindling and that mathematics and culture are correlated, it is necessary to teach mathematics in integration with cultural elements.One of the ways teachers can integrate cultural elements to lessons is by using ethnomathematics approach.Ethnomathematics is the study about the implementation of mathematical ideas, procedures, values, and practices developed by and related to certain cultural group in the context of the current time (Rosa & Gavarrete, 2017).Indonesian culture is so diverse, compared to other cultures.The diversity of cultures, languages, and ethnicities in Indonesia presents a promising potential to be studied in ethnomathematics framework.
Ethnomathematics study will keep growing in Indonesia and will reveal how unique Indonesian culture is compared to foreign cultures (Lidinillah et al., 2022).In addition to being Prima: Jurnal Pendidikan Matematika Vol. 7, No. 1, January 2023, 112-123 a means to preserve culture, ethnomathematics can also be implemented as an alternative to teach mathematics in a more contextual way, which will contribute to a successful mathematics learning.
Successful teaching of ethnomathematics has been proven by Japan and China in their mathematics lessons (Supriadi et al., 2016).Hence, ethnomathematics can be used as a means to develop students' love and pride for their own culture.It is in line with Ruseffendi (1992) who stated that mathematics should be taught not only by focusing on delivering material (lecture) but also by helping students develop their thinking and attitude.
Geometry is a topic in mathematics taught to students on every level of education.
Teaching geometry to students is important because it will develop students' reasoning, visual skills, verbal skills, logics, and practical implementation of mathematical concepts ( M u r s a l i n , 2 0 1 6 ) .In addition, geometrical concepts are found and used in daily life of the students.According to Kahfi (1996), geometry contributed to students' ability to analyze and prove their environment in terms of congruency, uniformity, and consistency.
The importance of geometry was also stressed by Allendoerfer (Kahfi, 1996) that through geometry, students would be able to connect mathematical concepts to the physical form of the world.Geometry developed students' ability to describe abstract mathematical ideas and to provide examples for mathematical systems.In other words, geometry would affect students' capability in relating or connecting ideas within mathematics discipline, between mathematics and other disciplines, and between mathematics and the real world.In addition, geometry would improve students' capability in presenting or describing the order in the world or in their environment.
However, Primary School students still have difficulties in learning geometry, particularly in terms of implementing geometrical concepts and principles and problem solving (Fauzi & Arisetyawan, 2020).Many factors contributed to students' low performance in geometry, including the teacher-centred learning process.Therefore, it is necessary to find a way to improve students' achievement in geometry because that basic topic of mathematics is important for students due to its close relation to daily life.
A study concerning ethnomathematics showed that ethno-pedagogy is an important element in learning in primary school level (Rahayu et al., 2021)

METHODS
Qualitative research method was implemented to obtained in-depth data, i.e.
meaningful data from the actual field.A qualitative study focused more on meaning than generalization.
The present study was conducted in three stages.On the first stage, data description, various data were gathered.On the second stage, data reduction/focus, the researchers focused the data found in data description into a particular topic.On the third stage, data selection, the researchers analyzed the topic in detail.
Data was obtained through observation and literature study and was supported by interviews with a primary school teachers representative and some Sumedang residents who worked in production and selling of bongsang.Ethnomathematics concepts in Sumedang tofu could be seen in the shape of the tofu, i.e. a cuboid or a cube.In teaching the topic of three-dimensional shapes, Sumedang tofu could be used as a demonstration media to explain about the volumes of a cube and a cuboid.
It could also be used to demonstrate how to identify the properties of a cuboid and a cube, including identification of diagonals in a cube and a cuboid.The placement of tofu on the bamboo sieve could be related to the concept of calculating the volume of a cuboid using non-standard units of measurement.Students could calculate the volume of the bamboo sieve by counting the number of tofu that could be placed on the sieve.

Figure 3. Identification of diagonals in a cube
Mathematical concepts, particularly geometry, could be found in the weaving pattern of Sumedang tofu container (bongsang).Bongsang could be used as a teaching media on the topics of circles, squares, and angles.Interview with a primary school teacher in North Sumedang Sub-district revealed that she had applied mathematical concepts of Sumedang tofu in teaching about threedimensional shapes to the sixth graders.However, it only touched on identification of the properties of three-dimensional shapes.She chose high quality tofu to bring to the class, so that it would not crumble easily when used in teaching.She observed that students' learning result improved when they studied the properties of three-dimensional shapes using Sumedang tofu.However, the teacher had not fully realized that ethnomathematics concepts could also be found in Sumedang tofu container (bongsang) and had not used it in teaching.
Her colleagues also had not realized the geometrical concepts found in bongsang.
Ethnomathematics shows how mathematics is related to the rich, diverse, and historically different tradition.Since everyone is unique and brought up in different environment, our mathematical thinking is shaped and affected by our diversity in language, religion, moral values, economic situation, and social and political activities (Rosa & Gavarrete, 2017).In line with Rahayu (Rahayu et al., 2021), using ethno-pedagogy based

FigureFigure 6 .
Figure 5. Weaving pattern of the bottom of bongsang

Figure 7 .
Figure 7. Transversal lines on bongsang weaving pattern . Another study on Panjalin One of the aspects of Sumedang culture is its local food, i.e.Sumedang tofu.Sumedang tofu is fried tofu sold in bamboo basket called bongsang.Everyone in Sumedang, from children to adults, is very familiar with Sumedang tofu and its bongsang because it is sold in almost every shop, store, or food stalls.Both Sumedang tofu and bongsang contain geometrical concepts.The tofu are cube-or cuboid-shaped.In the weaving process, the bottom of the bongsang formed a rectangle.The weaving patterns also formed geometric shapes such as parallelograms, hexagons, and transversal lines.Geometrical concepts of Sumedang tofu and bongsang could be used in teaching geometry to primary school students, in which they would connect geometrical concepts to Sumedang traditional food.The present study explored geometrical concepts found in Sumedang tofu and bongsang (Sumedang tofu basket).