Invastigation of fifth grade students' making sense of number size

In this study, it is aimed to investigate 5th grade students studying in Isparta to make sense of number size in natural numbers, fractions, decimal notions and percentages. The sample of the research consists of 400 fifth grade students studying in three public schools in the 2021-2022 academic year. Since it was aimed to determine the meaning of the number sizes of the students, the descriptive research model was used. The researcher developed a data collection tool consisting of ten questions about natural numbers, fractions, decimal notation and percentages. Data analysis was carried out in two stages. In the first stage, correct answers were coded as 1 and incorrect answers as 0. In the second stage, number sense-based answers were coded as 1 and rule-based answers were coded as 2, and the data were analyzed. As a result of the data obtained, it was determined that the fifth-grade students' understanding of number sizes was low in natural numbers, fractions, decimal notation and percentages. In addition, it was determined that students performed poorly in questions involving ordering in numbers and showing on the number line. It has been concluded that the performance of making sense of number size is highest in the field of learning natural numbers and the lowest is in decimal notation.