本研究之目的在於設計合乎解題條件的問題情境，協助學生發展合適的代數推理能力，並分析其在解題情境中表現的代數推理反應，提供教師辨識與推理證據的例證，提升教師推理教學的能力。本研究採個案研究方式，樣本取自南部一所公立小學三名五年級學童，利用研究者設計之「圖卡覆蓋」情境問題，配合訪談，進行作業資料的蒐集。資料採質性分析，分別以探索、分析、歸納及驗證等階段之表現加以探討，呈現出學生推理歷程策略之概念轉化之證據說明，研究者並根據個案在推理過程中之實際表現情形，提出建議，做為教師日後執行教學實務與方法改變的參考。

The main purpose of this study was to apply the tasks of cardboard covering, assist students to develop their capabilities of algebraic reasoning, and analyze their responses and performances on these tasks. The research findings could supply teachers with recognition and sense of student's abilities of algebraic reasoning and promote teachers' professional development. This research belongs to case study. The samples are from 3 fifth graders from manipulation, investigation and interviews. Data analysis was conducted with a qualitative aspect from students' four responses stages; exploration, analysis generalization and verification. The main results and finding were summarized and researcher provided four recommendations. In the future, teachers may apply them in their teaching practices.