DEVELOPMENT OF INSTRUMENTS TESTING STUDENTS' MATHEMATICAL CRITICAL THINKING SKILLS ONE-VARIABLE LINEAR EQUATION MATERIAL

,


INTRODUCTION
21st century skills in the field of education focus on developing 4C skills, namely critical thinking, creativity, collaboration, and communication (Widana et al., 2019).One field of science that can improve this ability is mathematics learning (Febriano et al., 2021).This is in line with what was stated by Novianti et al.,( 2020) which states that the ability to think critically is one of the levels of thinking needed to learn mathematics.The ability to think critically is the ability to think by using reflective reasoning and responsibly in solving problems that can be applied in everyday life (Sakinah & Nasution, 2023).Therefore, critical thinking skills need to be possessed by students.This is in line with what was stated Novianti et al., (2020) which states that by thinking, learners will have the habit of thinking deeply and living life with an intelligent, balanced and responsible approach.In addition, critical thinking skills are important for students in solving problems that occur in everyday life and in the face of very rapid technological developments (Nugroho et al., 2023).
There are several indicators that can be used to measure critical thinking skills.
According to Ennis, (1996) There are six indicators used to determine critical thinking skills, namely Focus, Reason, Inference, Situationon, Clarivity, and Overview.Meanwhile, according to facione (Karim & Normaya, 2015) There are four main critical thinking skills involved in the critical thinking process: interpretation, analysis, evaluation and inference.
Despite the fact that critical thinking skills are very important, the facts in the field state that the critical thinking skills of these students are still classified as low (Anggraini et al., 2022;Bakri et al., 2021;Lestari & Roesdiana, 2021;Novianti et al., 2020;Nuryanti et al., 2018).Based on research conducted by PISA (2018) shows that Indonesian students have an average mathematics score that is far below the international average.The score obtained by Indonesia is 379 from the international average score of 489 ranked 72 out of 78 countries (OECD, 2019).This is in line with what was stated (Tresnawati et al., 2017) The low critical thinking ability of students is caused because students are not used to solving non-routine problems, which in solving it requires students to think deeply.Based on the results of PISA, the test instrument must be in the form of story questions, where learners must understand the questions, present them systematically and relate them to the material that has been learned (Ratnamutia & Pujiastuti, 2020).
The material of one-variable linear equations (PLSV) is one of the mathematical materials that requires a strategy to solve it (Agustiani et al., 2022).However, according to (Ni'mah & Sutopo, 2018) It was found that mastery of the material and understanding of the concept of one-variable linear equations were still low, the learning outcomes were far from the minimum value that had been set.Therefore, a critical thinking ability test instrument is needed in accordance with the indicators that have been set on the one-variable linear equation (PLSV) material.In order to find out the extent of the quality of the instrument developed, the test instrument should

RESULTS AND DISCUSSION
The following are the stages and results of instrument development of students' mathematical critical thinking skills in one-variable linear equation material

1) Analysis
In this stage, researchers carry out observations and conduct interviews with mathematics teachers in MTsN 3Sukabumi with the results as presented in the following Based on the table above, it is known that the three questions obtained valid results because the calculation results  ℎ >   so that the instrument is said to be valid.

2) Reliability
The results obtained from the overall average of each question item showed that the student's mathematical critical thinking ability instrument had a reliability score of 0.467 with the medium category.According to Putri & Warmi, (2022) states that a value that has moderate reliability means that it is able to provide fairly stable results.

3) Differentiating Power
According to Arikonto, (2013) An instrument can be categorized as good if it has a distinguishing power with an index of 0.40 <  ≤ 0.70.The results of the distinguishing power of each test instrument item are as follows Table 3.

4) Difficulty Level
As for the difficulty level of the question items, there are two instrument items in the range of 0.30 <  ≤ 0.70 values with the medium category and one instrument item in the range of 0.00 <  ≤ 0.30 values, with difficult categories.According to (Bagiyono, 2017) item with difficulty levels in the difficult category can be used by having differentiating power in the medium and low categories and can distinguish upper and lower groups.

CONCLUSION
Based on the results and discussion, it can be concluded that the test instrument developed with the results of the validity analysis of each question item, reliability test, distinguishing power and level of difficulty is obtained that the instrument is good and can be used.
Of Instruments Testing Students' Mathematical Critical Thinking Skills One-Variable Oliah, Mulyanti, Nurcahyono need to be analyzed first.With the possession of the test instruments developed can be used to improve students' abilities.METHODS Development research using the ADDIE model.According to (Agustiani et al., 2022) ADDIE's development model consists of five stages including: Analysis, Design, Development, Implementation, and Evaluation.The subjects in this study were grade VIII G students at MTsN 3 Sukabumi with a total of 22 respondents.This study used validation sheets and tests of students' mathematical critical thinking skills.The validation sheet is used to verify the instrument tests students' mathematical critical thinking skills.Data analysis in this study was obtained based on the results of validation and the results of student answers.The analysis of test result data obtained based on student answers is a validity test, a reliability test of discriminating power, and the level of difficulty.

table . Table 1 .
Table Analysis results

Table 2 .
Table Question item validation results

Table Differentiating
Based on the table above, it can be seen that the three test instruments have a differentiating power with the same range of values, namely in the range of 0.40 <  ≤ 0.70, which is in the good category.