This study explored the impact of "Argumentation-driven inquiry" (ADI) on primary school students' argumentation performance in a blended synchronous learning environment (BSLE). A total of 159 fifth-grade primary school students (79 from an urban school and 80 from a rural school) participated in this quasi-experimental study. Students in the control group received inquiry-based (without argumentation) instruction in BSLE, while the experimental group students were instructed in an ADI approach in BSLE. Argumentation performance was measured before and immediately after the four-week research intervention. Results demonstrated that the remote (rural) school students in the experimental group scored significantly higher than remote (rural) school students in the control group on the Claim and Evidence dimensions, while no significant difference existed on the Reasoning and Counterclaim dimensions. The experimental group's onsite (urban) school students scored significantly higher on the Claim and Reasoning dimensions than the control group's onsite (urban) school students, though no significance was found in the overall score. This study also found that within the experimental group, the remote (rural) students scored significantly higher on the Evidence dimension of argumentation than the onsite (urban) students. The results of this study showed that in a BSLE, the ADI instructional approach had positive influence on the argumentation performance of primary school students in both rural and urban sites. Implementing ADI in BSLE could bridge the rural--urban gap in education and promote educational equity.