**5.1 Limitations**

Due to the sample size and the representativeness of the sample, generalizability of the results is a serious concern. More students with additional grade levels should be invited to participate in this kind of study. These factors should be considered by future researchers. In addition, two important issues not investigated in this study relate to the gifted students and number sense. Do the gifted students naturally have good number sense? How the number sense is developed by the gifted students?
