During the COVID-19 pandemic, teaching and learning activities had to be conducted fully online. To sustain quality education, teachers could use open educational resources (OERs) available in the public domain to make online mathematics teaching more effective and interactive. However, we currently know little about the use of OERs in primary school settings. Therefore, this study seeks to understand their school policies and guidelines on and teachers’ experience of using OERs during the pandemic. Our overarching goal is to provide recommendations on the future development and use of OERs in the context of primary school mathematics education. We employed a qualitative approach and interviewed 13 mathematics teachers from different primary schools. Our findings suggest that teachers tended to rely on OERs more during the pandemic than before. They used OERs to introduce mathematics and to facilitate class interactions in online lessons. However, not all schools had policies and guidelines on the use of OERs in place. Some teachers also encountered challenges when using OERs, such as finding that the resources were unsuitable for school contexts and lower primary school students. Based on the findings, we discuss some possible strategies for the improvement, such as ensuring the suitability of OERs, through developer–teacher collaborations.

Mathematical modeling is considered a bridge to STEM education and has been incorporated into K–12 mathematics curriculums in various countries. However, it has a relatively short history in Hong Kong schools. The lack of high-quality, relevant exemplars of mathematical modeling activities is a challenge to teacher practice in this area. Hence, this study aims to establish a design framework for mathematical modeling activities suitable for teachers and students in Hong Kong. We explore the design and content of the official mathematical modeling exemplars published by the Hong Kong Education Bureau using a document analysis approach. The findings provide the basis for developing a framework to be used in the future design of mathematical modeling activities. Four exemplars were found and analyzed in terms of their structural components, level of learning experience in mathematical modeling, and design characteristics. Based on our findings, we discussed various strategies to enhance the design of a mathematical modeling activity, including setting diversified learning objectives, cross-subject collaboration when formulating the problem context and instructions, designing more activities suitable for average and underperforming students, emphasizing the evaluation of modeling outcomes, and providing relevant supporting materials. Our study thus lays the groundwork for advancing the teaching and learning of mathematical modeling in school contexts.