The development and discriminant validity of the computerized dynamic number sense assessment system

The purpose of this study is to develop a computerized dynamic number sense assessment (CDNSA) system to investigate the issues of elementary students' number sense. Number sense is enriched by meaningful experiences and the performance is situated in specific content or context. Based upon our operational definition, three difficulty levels are developed to assess the students' number sense dynamically. The results show that the three difficulty levels of the CDNSA system could discriminate different ability levels groups successfully. It suggests that there is discriminative power in the CDNSA system for distinguishing different number sense degrees.