IMPLEMENTATION OF PROBLEM-BASED LEARNING (PBL) MODELS TO IMPROVE STUDENTS' MATHEMATICAL COMMUNICATION ABILITY

Math problem-solving skills among students are still lacking. This is demonstrated by kids' inability to comprehend inquiries, offer proper responses, or convey ideas. Low communication ability can also result from instruction that downplays the importance of students' ability to solve problems. This study aimed to determine whether the increase in the mathematical communication skills of students who received problem-based learning models was better than that of conventional learning. Moreover, to find out how students' attitudes toward problem-based learning models. This research method is quasi-experimental, and the research design is a Nonequivalent control group design. The experimental class gets learning with the problem-based learning model, and the control class with conventional learning. The population of this study was all students of class VII SMPN 2 Kota Mojokerto. The samples used were two classes of five selected by purposive sampling technique. To obtain research data, pretest, posttest, mathematical communication skills were used using the independent sample t-Test. Based on the results of data analysis, 1) improving students' mathematical communication ability using problem-based learning models is better than students using conventional learning; 2) students' attitude towards learning mathematics using the problem-based learning model is positive.


INTRODUCTION
Communication is the basis for growing mathematical knowledge orally and in writing.So mathematical communication is important in learning (Paridjo, 2018).However, based on the research that has been done by Sinaga & Manik (2019) that students' ability to solve math problems still needs to improve.This is marked by students' need to understand questions, provide answers, and express thoughts or ideas appropriately.Low communication abilities are also caused by learning models that have not emphasized students' problem-solving aspects (Madhavia et al., 2020).Teachers, as educators, have an important role in selecting learning models to help improve students' mathematical communication ability (Mardaleni et al., 2018;Triana et al., 2019).Based on other research (Herdin et al., 2018), the learning model of Problem-Based Learning shows that Praoblem-Based Learning is learning that supports positive achievement for problemsolving ability and mathematical communication ability.
Communication is one of the students' ability to convey something they know through dialogue events or mutual relations that occur in the classroom environment, where messages are transferred (Purnamasari & Afriansyah, 2021).The transferred message contains the transfer of mathematics material students study, for example, as a formula concept or strategy for solving a problem.Parties involved in communication in the classroom are teachers and students.Students' mathematical communication abilities need to be improved because, through mathematical communication, students can organize their mathematical thinking both orally and in writing (Sunardi et al., 2021), students can respond appropriately (Riyanti & Mardiani, 2021), both among students themselves and between students and teachers during the learning process takes place.
More mathematical communication ability will be needed to improve students' ability to use mathematical language to express mathematical ideas appropriately experiencing difficulties.They will impact the need for more ability to analyze and evaluate people's mathematical forecasts and strategies (Lutfianannisak & Sholihah, 2018).One of the causes of the low ability of students to communicate in mathematics is that the teacher is still the center of the learning process and dominates activities in class, thereby reducing student activity (Nurhanurawati et al., 2021).When learning occurs, most mathematics teachers only focus on students being skilled in answering questions, so the lack of mastery of students' mathematical communication ability needs to be handled (Pambudi et al., 2021).
Based on this, it is necessary to develop in the process of learning mathematics to help students improve mathematical communication skills (Sholihat et al., 2021); acquiring mathematical communication should emphasize real problem learning (Wardhana & Lutfianto, 2018).In problem-oriented mathematics learning, students are encouraged to explore existing knowledge and ideas about finding various strategies and solutions to problems.To help students understand mathematical concepts, one of the learning models related to real problems that can improve mathematical communication is problembased learning (Surya et al., 2018) | 701 requires students to communicate mathematically because this model presents real problems that must be converted into the mathematical language (Supriatna, 2020) One of the objectives of learning mathematics above is so that students can communicate symbols, tables, diagrams, or other media to clarify situations or problems.The ability that is measured is communication ability because it is needed so that students can apply it in solving problems.In addition to problem-solving and understanding mathematics, mathematical communication needs to be the focus of attention in learning mathematics because, through communication, students can organize their mathematical thinking and explore mathematical ideas.This is consistent with studies (Ningrum, 2016;Sartika, 2017) that claims problem-based learning can be employed as a learning model that can help students enhance their ability to communicate mathematically and have an impact on students' ability to communicate mathematically.
This study looks at problem-based learning, which can be used to help students communicate their mathematical ideas more effectively.It also looks at how problem-based learning has affected students at SMP Negeri 2 Kota Mojokerto.Based on the statement described above, the objective of the research is to apply Problem-Based Learning models to improve mathematical communication abilities.

RESEARCH METHODS
The research method used was quantitative research with a quasiexperimental design using a nonequivalent control group design.(Septian et al., 2022).The description questions given represent the indicators to be achieved.This study employs a Likert scale that includes four items: student's ability to produce many answers, their ability to apply mathematical symbols, and their ability to draw conclusions.Four response options are provided on this questionnaire: Strongly Agree (SS), Agree (S), Disagree (TS), and Strongly Disagree (STS).The attitude scale that will be used as a criterion for answers.

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difference between the pretest results of the experimental class and the control class.Meanwhile, for the posttest results, there was a significant difference between the posttest results in the experimental class which used the Problem Based Learning model and the control class which used conventional learning.

Gain Index Analysis of Students' Mathematical Communication Ability
Gain index data analysis was used to determine whether there were differences in the increase in students' mathematical communication ability after being given different treatments.The data were obtained from the pretest and posttest scores of the experimental and control classes.The gain index data from the two classes based on the high, medium, and low categories obtained are presented in Table 7.Based on Table 7, with a significant difference in the high category, the experimental class's improvement in conceptual understanding of mathematics outperformed the control class.In addition, there was one student in the low category in the experimental class.This demonstrates that the experimental class has improved more than the control class.However, a statistical analysis test was conducted to determine whether the rise was more significant.

Analysis of Students' Attitudes Towards Learning Mathematics Using a Problem-Based Learning Model
Data the attitude scale obtained is calculated and tabulated with the help of SPSS 26 software.In full, the student attitude scale scores are presented in Table 8.  (Hakiki et al., 2022) The drawbacks of this research are that there is only 1 SMP and a short time, so it needs to be done in many schools, and the time to prepare lessons is long.On the other hand, the advantage of the learning process with the problem-based learning model is that students will easily master the material because they are directly faced with everyday problems; worksheets also provide opportunities for students to communicate orally and in writing and develop their thoughts on the concepts encountered.Besides that, the goals to be achieved in the mathematics learning process can be optimal.
The study's findings indicate that there is an improvement in mathematics communication abilities in the experimental class using the problembased learning paradigm compared to the control class using traditional instruction.Research (Madhavia et al., 2020;Rianti Rahmalia et al., 2020) supports this.A student's ability to communicate with others and with the teacher allows them to exchange and convey their ideas, which can help them enhance their mathematical communication abilities.Ideas can be turned into communication material through discussion, reflection, and evaluation of student knowledge.Students will understand what is presented more clearly if they attempt to explain the conclusions of their thinking to other students in accordance with their capacities.

CONCLUSION AND SUGGESTION
Based on the findings and subsequent discussion, it is clear from this research that students' mathematical communication skills improve more quickly when using the Problem Based Learning model than when using conventional teaching methods.The

Table 4 .
Pretest data normality test results

Table 5 .
Postest data normality test results

Table 7 .
Gain index grouping data

Table 8 .
Data on students' attitudes toward learning mathematics using the problembased learning model