本研究目的在於探究個案教師課堂上對教科書多面體單元之教學活動調整類型，及影響調整之因素。以一位任教二十多年且有長期教科書編寫經驗的國小教師為對象，透過教學觀察、深度晤談與焦點座談以蒐集資料。結果發現，個案教師對教科書多面體單元之活動與佈題的調整類型包括：新增、取代、省略，以及重組等四類。影響調整之因素主要源自下述三個層面：（一）教科書的表徵，包括具體物表徵、任務表徵、概念表徵。（二）教師的個人知識與習慣，包括數學知識、學生學習數學之知識、數學教學知識、個人習慣與觀點。（三）情境脈絡，包括時間、教具數量、專家支持。最後，針對教科書設計、師資培育，及未來研究方向三方面做出建議。

The purpose of this study is to explore how a teacher adapts the textbook activity on polyhedron and what factors affect the adaptation. The data of this study was collected from a primary school teacher, also an experienced textbook editor, who has been teaching for twenty years; the method used includes classroom observation, in-depth interview, and focus group discussion. The teacher uses four types of textbook adaptation for activities and questions when she teaches students about polyhedron: addition, replacement, omission, and reorganization. Three factors may affect the adaptation. The first one is the representation of the textbook, which includes the physical objects, tasks, and concepts. The second factor is teacher's personal knowledge and habit which includes mathematics knowledge, knowledge of students' mathematical learning, mathematics pedagogical content knowledge, and personal habit and perspective. The last one is the context which includes time, quantity of teaching aids, and support from the experts. Last but not the least, this study makes suggestions on the design of the textbook, teacher training and important aspects of further study.