DESIGN OF A CONTEXTUAL INSTRUMENT FOR MEASURING MATHEMATICAL REASONING ABILITY IN SOCIAL ARITHMETIC
Siti Zahrotun, Novaliyosi, Cecep Anwar Hadi Firdos Santosa

Sultan Ageng Tirtayasa University, Magister Program

Abstract

The importance of reasoning ability in children is prioritized due to its urgency in understanding subject matter during the learning process. An appropriate instrument is needed to measure students^ mathematical reasoning skills so that educators can identify the suitable models, methods, and strategies for delivering the material. This study aims to produce a test item development instrument that has been validated and tested for reliability in assessing mathematical reasoning ability, specifically on the topic of Social Arithmetic.
The object of this research is one senior high school (SMA) in a city in Serang, involving 41 students from grade XI Science program as test subjects. This study uses a research and development method (Research and Development/R&D) based on the 4D model developed by Thiagarajan, which includes four stages: Define, Design, Develop, and Disseminate.
The instrument product was tested by classifying it based on difficulty level, discriminating power, and expert validity. The measurement was conducted using Microsoft Excel software. Five test items were produced, showing a low difficulty level (<1) and medium (<0.7), excellent discriminating power with scores >0.4, and expert validation results indicating a validity rate of 87.2%.

Keywords: Instrument, Contextual, Mathematical Reasoning, Social Arithmetic

Topic: STEM Education