2013 curriculum is the latest center of attention, especially in emphasizing the students’ understanding in learning mathematics not just only counting. The students understanding especially about these numbers can be seen from the students’ ideas to solve a problem. The students’ skills in solving the problem can be seen from their sensitivity to the numbers. This number sense ability can help the students’ performance by using some strategies that are useful for solving problems. Therefore, this study aimed to know the extent of number sense component possessed by VII H students at SMPN 3 Ponorogo. The subjects in this research were 30 students. The data collection used in this research was written number sense test result. This research was a qualitative descriptive study. The data that was obtained in this research such as the description of students’ number sense. The results indicated the ability of students based on component number sense, the lowest component number sense in recognizing the relative size of number and the students’ ability to decide wisely the strategies used from the calculation results. Overall, the average of students’ numbers sense was 50.78. Thus, it could be concluded that the ability of number sense that possessed by VII H students could be categorized as medium. However, the results of students’ work were still dominated by procedural understanding. The often problem faced by students were the lack knowledge about numbers concepts, the students used procedural ways, and the students did some errors in calculations.