The purpose of this study is to design an example activity based on Purdue Model (PM) about “The Arithmetic of Conscious Consumption” (ACC) unit for 7 th grade gifted students (GS) and non–gifted students (NGS) (25 G, 22 NG) in our country and to investigate the effects of this activity on critical thinking skills (CTS) and mathematical problem solving attitudes (MPSA) of these students. Eventually, it is concluded that the activity designed based on PM is more effective than the activities included in the National Education curriculum (NEC) on CTS and MPSA of G and NG students.