n light of national and international assessments indicating students' difficulties with rational concepts, which are considered crucial for future careers in STEM fields, we employed the certainty of response index (CRI) as an analytical method to examine the grasp of fundamental fraction concepts among a group of 40 seventh-grade students from the United Arab Emirates (UAE). By observing the errors and misconceptions displayed by the students, it was evident that more than 60% of the participants incorrectly assumed that adding fractions follows the same procedure as adding whole numbers. Furthermore, many students struggled to differentiate between the numerator and denominator. These findings suggest that the instructional approach employed failed to facilitate the necessary transition from whole number comprehension to understanding rational numbers. Drawing upon the theories of Dienes (1960) and Bruner (1966), we propose an alternative teaching method for addition and subtraction of fractions, wherein students construct their own comprehension of the rules using a graphing calculator as a tool for conceptual development.