The aim of this study is to determine the primary school fourth-grade students' understanding of four operation symbols, using them in arithmetic operations and word problems. Phenomenology research design, one of the qualitative research methods, was used in the research. The participants of the research consist of 123 students, attending the fourth grade of primary school (9 years old). The participants of the study were determined by using convenience sampling, The "four operation symbol study form" developed by the researcher was used as a data collection tool. Content analysis method was used in the analysis of the data. According to the results of the research, it was determined that the students formed meanings in different categories for the meanings of symbols, they were more successful in writing arithmetic operations by using symbols than in solving arithmetic operations. It was concluded that the students showed lower success in writing and solving word problems by using symbols compared to writing and solving arithmetic operations. It was determined that the lowest success in the use of symbols in arithmetic operations and word problems was in the use of the "=" symbol. [Note: The volume number (5) shown in the header on the PDF is incorrect. The correct issue number is 15.]