The purpose of this paper is to examine how lesson study can lead to teacher learning and improvement of instruction by developing teachers’ mathematical-task knowledge and by supporting teachers’ selection, modification, and implementation of mathematical tasks. Mathematical-task knowledge includes knowledge needed to use tasks that require a high level of thinking and reasoning.,A qualitative case study design was used to explore the learning and instruction of three teachers as they went through the process of lesson study, developed knowledge around mathematics tasks, and made changes to their instruction. Methods included direct observation of lessons, semi-structured interviews, and participant observation.,This lesson study project supported teachers in developing mathematical-task knowledge and in making change to instructional practice. The teachers discussed in this paper added to their understanding of mathematical tasks and changed how they implemented tasks after lesson study. The teachers began to challenge students to go beyond memorizing or executing procedures to deepen the students’ understanding of mathematical concepts. Teachers developed key insights and understandings of mathematical tasks, triggering shifts in their thinking, and changes to instruction. Collaboration and reflection altered the selection, modification, and implementation of mathematical tasks.,This study reveals the connections between features of lesson study and the pathways that lead to learning and improvements to instruction. Limitations included the demands of the school district’s pacing guide and curriculum, and a limited number of interviews and observations were conducted after lesson study.,There are many different ways lesson study has been implemented in the USA, yet the effectiveness of many lesson study projects is still unclear. This study reveals more about the lesson study process, what features are important, and how these features lead to development of knowledge and practice. This study examines how teachers within the same lesson study group added to their knowledge and practice and how different features of lesson study prompt them to make changes.

中文翻译：

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通过课堂学习发展教师的数学任务知识与实践

本文的目的是研究课堂学习如何通过发展教师的数学任务知识和支持教师选择、修改和实施数学任务来促进教师的学习和教学的改进。数学任务知识包括使用需要高水平思考和推理的任务所需的知识。,使用定性案例研究设计来探索三位教师在经历课程学习过程中的学习和教学，围绕数学任务，并改变了他们的教学。方法包括直接观察课程、半结构化访谈和参与式观察。该课程研究项目支持教师发展数学任务知识和改变教学实践。本文讨论的教师增加了他们对数学任务的理解，并改变了他们在课后执行任务的方式。教师开始挑战学生超越记忆或执行程序，以加深学生对数学概念的理解。教师对数学任务有了重要的见解和理解，引发了他们思维的转变和教学的变化。合作和反思改变了数学任务的选择、修改和实施。,这项研究揭示了课程学习的特征与导致学习和改进教学的途径之间的联系。限制包括学区步调指南和课程的要求，并且在课后进行了有限数量的访谈和观察。,在美国实施了许多不同的课后学习方式,但许多课后学习项目的有效性仍不清楚。这项研究揭示了更多关于课程学习过程的信息，哪些特征是重要的，以及这些特征如何导致知识和实践的发展。本研究考察了同一课程学习小组中的教师如何增加他们的知识和实践，以及课程学习的不同特征如何促使他们做出改变。以及这些特征如何导致知识和实践的发展。本研究考察了同一课程学习小组中的教师如何增加他们的知识和实践，以及课程学习的不同特征如何促使他们做出改变。以及这些特征如何导致知识和实践的发展。本研究考察了同一课程学习小组中的教师如何增加他们的知识和实践，以及课程学习的不同特征如何促使他们做出改变。