Student Errors in Completing Mathematical Story Problems Based on Watson's Criteria During Pandemic COVID-19 Malim Muhammad {malim.muhammad@gmail.com} Department of Mathematics Education, Faculty of Teacher Training and Education, Universitas Muhammadiyah Purwokerto Abstract. This study aims to describe students' mistakes in solving story problems based on the Watson Criteria. The material used in this study is a two-variable linear equation system and was implemented at SMP Negeri 1 Kembaran. This type of research is a qualitative description. The subjects of this study were students of 7th grade class who were selected through purposive sampling technique. Students are grouped into three groups, namely groups of students with high, medium, and low learning achievement. Three students were selected from the three groups. Data collection techniques using written tests and interviews. The data validation test used technical triangulation by comparing the results of written tests and interviews. The results showed that 1) high learning achievement students made mistakes in the response level conflict stage, missing conclusions, missing data, and indirect manipulation; 2) student learning achievement is making mistakes at the stage of the problem of skill hierarchy, response level conflict, missing conclusions, missing data, and indirect manipulation; and 3) students with low learning achievement made mistakes at the stage of incorrect data, skill hierarchy problems, inappropriate procedures, response level conflicts, missing conclusions, missing data, and indirect manipulation. Keywords: Student Errors, Watson's Criteria, Mathematical Story Problems, COVID-19 1 Introduction The learning process in schools is the best effort to increase knowledge and skills. In addition, many students think that school is a very fun activity, they can interact with each other. Schools can improve students' social skills and social class awareness. But now the activity called school has stopped suddenly because of the Covid-19 interference. For Indonesian families is a big surprise especially for the productivity of parents who are usually busy with work outside the home. Likewise with the psychological problems of the children of students who are accustomed to face-to-face learning with their teachers. Mathematics has a big role in everyday life, it can be seen that when learning mathematics, someone will learn to plan, decide, and anticipate problems that come [1]. In solving mathemaical story problems, cognitive skills, understanding of symbols, and understanding of sentences are needed [2]. Mastery of students' math skills needs to be analyzed [3]. It aims to determine the extent to which students understand the material given. Mathematical story problems related to everyday life [4]. Mathematical story problems are a problem that can help students apply mathematical concepts in everyday life [5]. AECon 2020, December 19-20, Purwokerto, Indonesia Copyright © 2021 EAI DOI 10.4108/eai.19-12-2020.2309186