ETHNOMATHEMATICS: EXPLORING THE ACTIVITIES OF DESIGNING KEBAYA KARTINI

The study aims to explore the correlation between mathematics and culture, especially in the activities of designing Kebaya Kartini. This research uses ethnography approach, that is an empirical and theoretical approach to get the description and deep analysis of a culture based on the field note obtained from the data collection. The result shows the activities of designing Kebaya Kartini have the concept of mathematics, such as the angle, measure, and integer operations.

for students moreover required by everyone in daily activities to develop the ability of logical, systematic, critical thinking of students, and to support their learning success in the future (Niess, 2005;Runisah, et al. 2017;Prahmana and Kusumah, 2016).On the other hand, mathematics is an inherent knowledge in the activities of life and very close to the culture in the context of the behavior or habit that has existed since ancient times and for generations (Prahmana, et al. 2012;Muhtadi, et al. 2017;Risdiyanti & Prahmana, 2017).Therefore, mathematics could be said as the one of subject that is very important and needed in everyday life because it can increase students' thinking ability.
When we study of Ethnomathematics, it does not mean we only examine the mathematical phenomenon and translated it into a formal mathematical concept (mathematical modeling).However, more than that, the way of thinking and the underlying values why a particular individual or group can have such an understanding like that is also interesting to learn (Arisetyawan, et al. 2014).Ethnomathematics has as its source the activities that a person/group performs and the knowledge they have resulting from the needs of their daily lives.It assumes dynamic sharing between activities and knowledge; values popular knowledge production; and proposes education as a process in which knowledge transmitted across generations (Biembengut, 2016).Ethnomathematics explores the interaction of academic and cultural ways to provide inclusive developmental programs for diverse populations served by educational institutions (Rosa, et al. 2016).The cultural mathematics of cultural groups is considered part of their life characteristics and developed by the cultural group and serves their natural interests, which derive from their social situation (Fouze & Amit, 2018;Anderson, 1990).Therefore, teachers have a large influence over shaping the boundaries between the two fields of formal mathematics and Ethnomathematics and on the comprehensive integration of daily mathematical activities into mathematics.
Indonesia is one country in Asia with a population that is multicultural.One of them is the activity of design Kebaya.It is one of the traditional dresses in Indonesia.Kebaya is a dress with buttons open on the front and paired with traditional fabric.One type of Kebaya that exists in Indonesia is Kebaya Kartini (KK).

METHOD
The methodology used in this research belongs to the exploratory research methods, the research excavation.It means that the methods are to find and to know a phenomenon or event (concept or problem) with conducting an assessment of the symptoms (Gulo, 2000;Prahmana, 2017).Moreover, in the process using an ethnographic approach, is an empirical and theoretical approach, aiming to get a description and a thorough analysis of culture based on field research.How people organize their culture in mind and then use in life.Ethnographic tasks to finds and describe the organization of the mind (Spradley, 2007).The procedure of research conducted adopting ethnographic approach by Spradley (2007), includes the following steps: establish informants, conducting interviews with informants, making notes ethnographic, ask questions descriptive, analyzing the results of ethnographic interviews, create a domain analysis, asking questions of structural, conduct taxonomic analysis, and writing ethnography.

RESULT AND DISCUSSION
The results showed that Ethnomathematics found in the design KK in LPK Nusa Indah Gunungkidul.Ethnomathematics in KK designing activities can be seen from the process of making patterns on the back, front, and hand.The figure 1 is a picture of KK, which consists of a pattern of the back, a pattern of the front, and a pattern the hand.a.The angle To start making a pattern, first have to drawing the angle of the elbow BAC (Figure 1 and 2).b.Measure To determine the size of KK, it should first be measured the length of the desired Kebaya, body width, back width, waist width, thigh width, arm length, arm width, and armpit.

c. Integer operation
The body size of the person who will use the KK, the basis for calculating the size of the KK pattern to be made.To calculate the size of the pattern, the students are using the concept of fractional operation.
To make a pattern of the back (Figure 1 To make "kupnat" same with a pattern of the back.In the design Kebaya Kartini to apply the concepts of mathematics including the number operations, plane, line, and angle.To make Kebaya Kartini pattern, it needs drawing skills and calculating skills.Drawing skills are need when drawing corners to begin drawing patterns.The calculating skills are need when calculating the size of the Kebaya Kartini pattern.The results are supported for several researches that stated that cultural as context would be important thing in learning process (Abdullah, 2017;Zaenuri & Dwidayati, 2018;Ditasona, 2018;Hariastuti, 2017;Sari, et al. 2018;Putri, 2017;Wahyuni & Pertiwi, 2017;Sudirman, et al. 2017;Pratikno, 2018;Muchsin, et al. 2014).Furthermore, the position in this research is to introduce Kebaya Kartini as a starting point in learning mathematics that has not been studied by previous researchers.

CONCLUSION
Ethnomathematics activity on the designing of Kebaya Kartini is very diverse.The process is starting from drawing angles, measure, and calculating the size of the pattern with the concept of integer operations.The culture is very important is embedded in students early on.Learning math based on culture can become a solution to introduce the culture and learning math.The result shows that in the activities of designing Kebaya Kartini have the concepts of mathematics, such as number operations, plane, line, and angle.
Figure 1.The Pattern of the Back

Figure 2 .
Figure 2. The pattern of the front