<![CDATA[Online learning became a necessity in many places during the COVID-19 pandemic. In the case of Hong Kong SAR, the pandemic provided a unique opportunity to establish blended learning as a norm. The authors discuss the insights and challenges related to delivering mathematics lessons online in a secondary school during and after the pandemic. A three-year-long case study was conducted to examine the differences in perceptions between a teacher and his five students regarding online mathematics instruction during the suspension of traditional in-class lessons in 2020 and after the resumption of traditional instruction in 2023. The Social-Ecological Approach with domains of structure, agency, and cultural practice was applied in the study, which investigated the perceived benefits of blended learning for both the students and the teachers. Data was collected via interviews. The study explored technological challenges, curriculum adaptations, and the impact of parental support on blended learning. Looking ahead, leveraging motivators like easy access while mitigating distractors through disciplined strategies can optimize blended learning environments. The insights gained from this study provide valuable guidance on the effectiveness of instructional strategies and technological tools, highlighting the features of best practices for future blended learning approaches. Furthermore, the paper provides valuable information for policymakers, educators, and educational technology developers.]]>
