本研究目的在探討國小學童的小數知識，主要了解國小學童在學習小數方面的表現情形與常犯的錯諤。取樣學童來自高屏地區的三所學校，每校四、五、六年級學童各一班，共9班總計329人;他們是接受數學舊課程的最後一批國小學童。評量工具為自編的筆試試題，包括小數的概念和小數的計算兩部分，作為探討國小學童學習小數知識之依據。資料收集以筆試和訪談為主。資料分析以敘述統計和內容分析法為主。研究發現這些學童在小數的表現上並鎮理想，他們所獲得的小數知識似乎都偏向程序性的了解或以記憶性的居多。此外，學童常犯的錯誤在概念是部分有: 1.學童有「乘會變大，除會變小」的迷思概念。 2.學童在小數除法上，會以「大的數」÷「小的數」來解題。 3.學童直接將分子與分母當作整數與小數部分或小數與整數部分。 4.學童會以小數位數的多寡來判斷小數的大小。 在計算題部分有: 1.學童以整數加法的經驗類推，而易將數子「向右對齊」計算。 2.學童在求餘數問題中常以四捨五入法求商。 3.學童在求有餘數的除法中，會忽略餘數的小數點，或是將餘數的小數點對齊移位後的被除數小數點。

　　　　　 The study explored elementary school students' knowledge of decimals in two parts, decimal concept and decimal computation. The subject were 329 students in grades 4, 5, and 6 from nine classes in three elementary schools located in south Taiwan. Data was collected from a written test and an interview. Data analysis was a combination of quantitative ad qualitative methods. The main results and findings indicate that elementary school students' knowledge of decimals seems to be largely procedural. There appears to be a lack of basic understanding of decimals, particularly decimal meaning and place value. In addition, some of these students hold misconceptions such as multiplication makes bigger and division makes smaller. Comments and suggestions are presented.