Penelitian ini bertujuan untuk mendeskripsikan kesalahan mahasiswa PGSD dalam menyelesaikan soal numerasi ditinjau dari aspek self-efficacy. Penelitian menggunakan pendekatan kualitatif deskriptif dengan subjek tiga mahasiswa yang dikategorikan berdasarkan tingkat self-efficacy: rendah, sedang, dan tinggi. Data dikumpulkan melalui angket, tes numerasi, dan wawancara, serta dianalisis menggunakan tahapan Newman. Hasil penelitian menunjukkan bahwa mahasiswa dengan self-efficacy rendah melakukan kesalahan pada tahap membaca. Mahasiswa dengan self-efficacy sedang dan tinggi menunjukkan kesalahan dalam memahami soal, yang mengakibatkan muncul kesalahan pada transformasion, Prosess skill dan Encoding. Penelitian ini menegaskan pentingnya mengetahui kesalahan dalam menyelesaikan soal numerasi untuk meningkatkan kemampuan berhitung mahasiswa.
Kata kunci:Kesalahan Numerasi, Pemecahan Masalah, Self-Efficacy, Mahasiswa PGSD

Developing numeracy skills in students is essential, yet little is known about how self-efficacy influences the specific errors they make while solving quantitative tasks. This study aimed to describe the errors committed by the students in solving numeracy problems in terms of the aspect of self-efficacy. This qualitative descriptive study was employed, which involved three students in the Primary School Teacher Education (PGSD) Department at Borneo Tarakan University, each representing a different self-efficacy level. low, moderate, and high. Data were gathered through a self-efficacy questionnaire, a numeracy test, and interviews, and were analysed using Newman's problem-solving stages reading, comprehension, transformation, process skills, and encoding Findings revealed different error profiles. The low-self-efficacy student struggled primarily at the reading stage Meanwhile, the moderate and high-self-efficacy students made errors at the comprehension stage, in this case errors in understanding the problems, which further led to errors in transformation, process skills, and encoding This study emphasized the importance of identifying and addressing student errors in numeracy problem-solving, particularly in relation to their self-efficacy, as a means to improve overall numeracy skills Keywords: Numeracy Errors, Problem Solving, Self-Efficacy, PGSD Students