Teachers’ noticing of students’ mathematical thinking plays an important role in supporting student learning. Yet little is known about how online professional development (PD)—a growing setting for PD in the USA—can cultivate this noticing. Here, we explore the potential of using two online tools for engaging video to support K-2 teachers’ noticing of students’ mathematical thinking in the context of a six-week online video-based PD program. While participating in the program, teachers used a commenting tool that allowed them to view video in its entirety and write a summary note, as well as a tagging tool that allowed them to mark moments of video while viewing and associate notes with those moments. We found that teachers’ regular use of the tagging tool promoted their increased noticing of students’ mathematical thinking in video. Further, the tagging tool and commenting tool appeared to function in complementary ways to support teachers’ noticing. These findings contribute to the field’s growing understanding of how technological advances can support the development and study of mathematics teacher noticing, with implications for the design of online teacher learning environments.

教师对学生数学思维的关注对支持学生的学习起着重要的作用。然而，人们对在线专业发展 (PD)（在美国日益增长的 PD 环境）如何培养这种关注知之甚少。在这里，我们探讨了在为期六周的基于在线视频的 PD 计划的背景下，使用两种吸引视频的在线工具来支持 K-2 教师注意学生数学思维的潜力。在参与该计划时，教师们使用了一种评论工具，使他们能够完整地观看视频并撰写摘要笔记，还使用了一种标记工具，使他们能够在观看视频时标记视频时刻并将笔记与这些时刻相关联。我们发现教师经常使用标注工具促进了他们对视频中学生数学思维的更多关注。此外，标记工具和评论工具似乎以互补的方式发挥作用，以支持教师的注意。这些发现有助于该领域加深对技术进步如何支持数学教师注意的发展和研究的理解，并对在线教师学习环境的设计产生影响。