Stefani Putri Andrianti, Indriati Nurul Hidayah
Reasoning plays an important role in helping students solve mathematical problems, including numeracy problems. This research aims to describe students' errors in solving numeracy problems on the application of trigonometric comparisons based on the Hadar criteria in terms of students' reasoning. This research also looked for the causes of student errors. This research was conducted in class XI of Frateran Catholic High School Surabaya with instruments such as reasoning tests, numeracy tests, and interview guidelines. This research used a descriptive method with a qualitative approach. Based on the reasoning test results, students were grouped into high, medium, and low reasoning groups. Through the purposive sampling technique, one student was taken from each group. The results of the study identified specific errors made by students in solving numeracy problems based on Hadar's criteria. Students with low reasoning ability made errors in all criteria, including errors in the use of data, language, and logic in drawing conclusions, definitions or theorems, answers were not rechecked and did not recheck work. Students with moderate reasoning ability made several errors, namely errors in the use of data, language, logic in drawing conclusions, definitions or theorems, and technical errors. Meanwhile, students with high reasoning ability only made one error, namely an error in the use of language. © 2025 American Institute of Physics Inc.. All rights reserved.
Mathematics Department, Universitas Negeri Malang, Jalan Semarang 5, Malang, 65145, Indonesia
