本研究旨在了解原住民幼兒學習數的合成與分解的歷程，並探究在結合生活經驗轉化而成的數學遊戲後，原住民幼兒學習數的合成與分解的成效。採質性研究的方法，運用教師自行設計的數學教學活動，引導幼兒學習數的合成與分解，並透過遊戲方式讓幼兒獨立操作，建構數的合成與分解的概念。藉由觀察記錄、訪談紀錄與教師的教學省思等資料，呈現原住民幼兒學習數的合成與分解的歷程。研究結果發現：1.在數學遊戲教學活動中，原住民幼兒在「1-10的合成與分解」會發展出不同解題策略。2.教師自行設計的數學教學活動須結合幼兒生活經驗融入日常生活的情境，較能引發幼兒思考促進理解。3.透過「數的合成與分解」教學活動後，三位原住民幼兒均呈現進步現象。

This qualitative study aims to understand the learning process of number composition and decomposition for indigenous preschoolers and investigate their learning outcomes with the use of math games developed by combining their life experiences. In the study, a kindergarten teacher taught three indigenous preschoolers to compose and decompose numbers with the self-developed teaching activities and to establish their concept of number composition and decomposition by letting them practice independently through games. Through classroom observations, interviews, and teaching reflections, a process of the indigenous preschoolers’ learning of number composition and decomposition is presented. The findings are as follows. (1) The indigenous children could develop different resolution strategies through 1-10 composing and decomposing math games. (2) Math teaching activities self-developed by teachers should combine preschoolers’ life experiences and their daily life situations so as to better increase their thinking and understanding. (3) All of the three indigenous preschoolers showed improvements after the “Number Composition and Decomposition” teaching activities.