本文旨在透過佈題、觀察幼兒的操作與解題、推測幼兒可能擁有的數概念，以及再佈題與驗證（或修正）之歷程，針對中部地區一所托兒所中、大班幼兒的正整數數概念發展概況加以探究，並試著針對探究的結果於幼兒數學教育之意涵加以闡述：首先，就幼兒數概念的發展而言，本文除呈現4.5-5.0歲、5.0-5.5歲、5.5-6.0歲及6.0歲以上幼兒的可能發展，還指出女生的發展未必較快、家長的引導提供幼兒發展的機會，但可能因未考量幼兒的發展而未必有利，以及幼兒解比較型問題的能力之發展慢於解合成型和取走型問題之能力。其次，就本研究於幼兒數學教育之啟示來說，本文指出一項應再行思考之事項與五點教學原則，供幼教工作者參考。

This paper investigated the positive integral number concept development status of young children who were attending senior or intermediate classes of a kindergarten, located in central Taiwan. The approach used included problem posing, observing young children’s’ behaviors and question solving approaches. We then could conjecture the number concepts the young children possess, then re-posing problems and verifying (or revising) estimates. Further, this paper attempted to elaborate the implications of the results for young children’s mathematics education: First, findings show the possible number concept developments of 4.5-5.0 year olds, 5.0-5.5 year olds, 5.5-6.0 year olds, and 6.0 year olds and above. Results indicate the development of female young children may not be faster. Parent guidance provides the opportunity for young children’s’ development but may not be beneficial. Development of young children’s’ solving comparison problems ability is slower than developments of abilities for compound problems and take-away problems. Second, this paper raises implications for young children’s mathematics education. Suggestions regarding the contents of young children’s’ mathematics education and 5 teaching principles for young children educators are proposed.