LEARNING SETS THEORY USING GAPLE CARDS: A STUDY OF EAST JAVA ETHNOMATHEMATICS

Students' interest in learning mathematics in Indonesia still needs to be improved. Efforts can be made by providing creative learning in the classroom, one of which is by linking mathematics and culture, known as ethnomathematics. Ethnomathematics can be used as a learning innovation to motivate students to learn mathematics. Therefore, this study aims to explore the concept of mathematics in one of the traditional game cultures still developing in Malang, East Java, namely Gaple . Gaple cards can be used as a media for learning mathematics in set material linked through the Realistic Mathematics Education (RME) approach. This study used a descriptive qualitative method with an ethnographic approach, which describes the results of the ethnomathematics exploration of the Gaple card game. Data collection uses observation, interviews, literature review, and photo documentation to explore ethnomathematics elements on gaple game cards. Exploration results were obtained by observing the number of points on each gaple card, namely the concept of universal sets, intersections, unions, and complements. These results are then packaged in a table of learning activities by implementing the three stages of the RME approach.


INTRODUCTION
Students' interest in learning mathematics is still relatively low.On the other hand, it is known that mathematics is basic knowledge and is considered the mother of all branches of science.Therefore, mathematics is essential to learning at every level of education (Yusuf Aditya, 2016).The preliminary study shows that students' interest in studying mathematics has yet to reach half the number of students in the class (Friantini & Winata, 2019;Sucipto & Firmansyah, 2021).The common factors that cause these problems are teacher is too monotonous in giving material during the learning process in class.This situation affects in students' interest of mathematics and gives rise to the perception that mathematics is difficult to learn (Putri et al., 2019;Firdaus, 2019;Sarah et al., 2021).Thus, it is necessary to make an effort to attract students' interest in learning mathematics.
One of the efforts that can be made in order to students are interested in learning mathematics when in class is that the teacher must be able to deliver material creatively.This can be done using the right approach or engaging learning media so that learning in the classroom is more meaningful, fun, and not monotonous.Learning mathematics using a cultural approach will be more meaningful and help students become more active in class and explore their culture (Shahbari & Daher, 2020;Supriyadi et al., 2020).Learning linking mathematics and culture is called ethnomathematics (Cimen, 2014).Further, ethnomathematics can be used as a learning innovation that makes students love mathematics more, motivated to learn, and more creative through culture.
D'Ambrosio coined ethnomathematics to express mathematics in cultures that can be identified and perceived as the study of mathematical ideas in every culture (Sarwoedi, 2018).Ethnomathematics is a study of mathematics that connects mathematical objects with the actual cultural environment (Kurniawan et al., 2019;Sulistyani et al., 2019).According to Delviana et al. (2022), ethnomathematics is considered as a media to see and understand mathematics as a cultural product.Therefore, students will more easily understand the material if they depart from contextual and cultural issues (Zaenuri & Dwidayati, 2018;Rahayu et al., 2019).From these various opinions, ethnomathematics is one of the right strategies to be used in classroom learning so that students can easily understand mathematical material.
Ethnomathematics can be integrated into various cultures in Indonesia.Many cultures contain mathematical concepts, one of which is in the traditional Gaple game.Gaple is a traditional game that is still developing in the community, to be precise, in Malang, East Java.However, this Gaple game is played in Malang and all regions of Indonesia.It is just that each region has different rules.In playing Gaple cards, there are general and special rules.There is something that makes each region different, namely the special rules.
The mathematical studies on the Gaple card can be used as learning media for material sets.The sets is one of the mathematical materials that are still problematic for students, and the factor is due to differences in the ability of each student (Fauza et al., 2017;Listiana & Sutriyono, 2018).Besides, there is a teacher factor that is still relatively monotonous in delivering material (Dwidarti et al., 2019;Falah et al., 2021).Therefore, creating a more meaningful learning atmosphere through creative learning media is necessary to achieve the learning objectives in the set material.
There have been several studies on the use of traditional games as learning media that have been carried out with a focus on studying the concept of plane geometry, relationships between angles, and the concept of transformation geometry in the Deqklak game (Fauzi & Lu'luilmaknun, 2019), studying the concept of geometric shapes on the Pikachu game card (Fitria et al., 2019), the study of the concepts of addition and multiplication in the mangosteen fruit guessing card game (Hariastuti R, 2017).However, there are still needs to be a study of the Gaple cards because Gaple is a local culture that is easy to find in every region.In addition, if learning is introduced from its own culture, it will attain students' interest in learning mathematics.Therefore, researchers are interested in conducting a study on the Gaple cards.The findings obtained on this Gaple card are the concept of sets, including universal sets, intersections, unions, subsets, and complements.
The results of this finding can be used as one of the mathematics learning media in the classroom, especially in set material linked to the Realistic Mathematics Education approach.RME is an approach that involves students practicing natural objects in the learning process to attract students to learn mathematics (Dewimarni et al., 2022).Therefore, in this study, using the RME approach is associated with the findings obtained because students can practice directly with natural objects, namely Gaple cards in classroom learning activities.

METHODS
This study used a descriptive qualitative method with an ethnographic approach, which describes the results of ethnomathematics exploration of the Gaple card game in the form of a set material concept.Data collection techniques used observation, interviews, literature review, and photo documentation to explore ethnomathematics elements on Gaple cards.
Observations and interviews were conducted to find out the rules for playing Gaple in the city of Malang, which took place in a coffee shop with most visitors still playing Gaple.Furthermore, to find the mathematical side, it is only focused on the number of Gaple card points to document each card, conduct a literature review, and obtain information from Gaple cards and set material.

RESULT AND DISCUSSION
After conducting observations and interviews with visitors playing Gaple cards, the results obtained are the rules of the Gaple game, while the set concept consists of the number of dots on the Gaple cards.

Gaple Game Rules in Malang
Gaple game must be played with four people.The Gaple card contains 28 cards, which are then distributed seven cards each to each player.The game rules in this area are for those with a "blank" card as the first player (put down the first card after being shuffled).More details can be seen in Figure 1.Furthermore, if players still need to get the type of card to lower, they will be skipped.After that, it repeats until the end of the game.The game ends when one of the players has Gaple.
The following is the condition of the game after Gaple, which can be seen in Figure 2.

Figure 2. End Game Conditions
Determine who loses and wins.It can be seen from the remaining number of dots on each player's card at the end of the game.The loser is the player who has the most remaining number of card points.Figure 2 shows that the third player loses.

Sets Concept in Gaple Cards
In each Gaple game card, there are two sides.There are many dots on each side of the card; more details can be seen in Figure 3.

Figure 3. Two sides of Gaple Card
In Figure 3. the two cards have many points, which can be written as (6,0) and (5,0).Regardless of the order, this means (6,0) equals (0,6) and (5,0) equals (0,5).Then, after being observed, there are dots on the side of each card that are sequential to each other.For example, for points that add up to 6 from side A, this means that there are cards that have consecutive points, namely (6,0), (6,1), (6,2), (6,3), (6, 4), (6,5), and (6,6).More details can be seen in Figure 4.In Figure 4, the order of all Gaple cards can be easily defined in a set.The sets that contain all defined objects are called the universal sets (Sholikhah & Masriyah, 2022).Thus, indirectly, if we are going to group all Gaple cards using the concept of a universal set, expressed mathematically as follows.

Figure 5. Card members 6
Based on Figure 5, card 6 members can be expressed in mathematical form as follows.
5 = {  ∈  |  is a member of card 5} This also applies to other card members, namely card members 4, 3, 2, 1, and card 0, which are also analogous to K6 or K5.
Next, look at the sets of all Gaple cards and the sets of card 6, which states that all members of card 6 are members of all Gaple cards.In the basic concept of sets, there is the term subsets, which is a condition when all members of sets are members of other sets (Arfiyanti & Irawan, 2017).So, in this case, it is concluded that card 6 is a subset of all Gaple cards.In mathematics, it can be written as follows.
6 cards are all ⊂ Gaple cards Let K6 be the sets of 6 cards, and S be the sets of all Gaple cards.So, it can be denoted as follows.

Figure 7. Concept of Sets Intersection on Gaple Cards
Based on Figure 7, cards in member 6 with many dots (6,5) can be included in member 5, namely (5,6), because they are on the same card.Likewise, cards in member 5 with many dots (5,4) can enter card member 4, that is (4,5), because they are in the same card, and so on.So, in mathematics, this is included in the concept of intersection.A set with members in sets A and is called an intersection (Prahmana & Istiandaru, 2021).The intersection of two sets is denoted as "∩".More specifically, suppose two examples of cards 6 and 5 are taken to be written mathematically as follows.
Based on the statement submitted, using the RME approach is appropriate to be associated with the exploration results on the Gaple card.The suitability of Gaple cards and the RME approach can emerge when students understand the pattern of the number of dots on each card from one side and when students can group cards sequentially based on the card pattern so that the Gaple card associated with the RME approach can be used as a learning media for mathematics in the classroom to support students' understanding of the primary set concept material in seventh-grade junior high school.
The implementation of RME in the classroom includes three stages, namely (1) the introduction stage, (2) the exploration stage, and (3) the summarizing stage (Van den Heuvel-Panhuizen & Drijvers, 2014).Based on the three RME stages, the researcher describes them according to the needs of this research related to the use of Gaple card learning media using the RME approach to the basic concept of sets.This is packaged in a learning activity shown in Table 1.

RME Stages
Learning Path Learning Activities

Activity 1
Gaple cards to be introduced that Gaple is a traditional game related to the concept of sets.
Students observe Gaple cards, which show that each card has dots from two sides of the card.

Activity 2
Students begin to explore to find problems by grouping Gaple cards.
• Students understand the pattern of card dots from one side.
• Students begin to group cards in sequence based on the pattern of the number of dots understood from one side of the card.
• Students discover the concepts of universal sets, subsets, intersections, and complements on Gaple cards.

Summarize Activity 3
Write down the sets of Gaple cards Students define the sets of cards that have been sorted and write subsets, unions, intersections, and complements.

Figure 1 .
Figure 1.First Player with Blank Card

Figure 4 .
Figure 4 .Sequence of Gaple Cards Based on Side A

Figure 8 .
Figure 8. Illustration The Intersection of Sets on Gaple Cards in a Venn Diagram