Question

12．根據(jù)前面幾個數(shù)的規(guī)律，在括號里填上適當?shù)臄?shù)．$\frac{6}{5}$，$\frac{2}{5}$，$\frac{2}{15}$，$\frac{2}{45}$，$\frac{2}{135}$，$\frac{2}{405}$．

Answer 1

分析 $\frac{6}{5}$÷3=$\frac{2}{5}$，
$\frac{2}{5}$÷3=$\frac{2}{15}$，
后一個數(shù)是前一個數(shù)除以3得到的；由此求解．

解答 解：$\frac{2}{15}$÷3=$\frac{2}{45}$，
驗證：$\frac{2}{45}$÷3=$\frac{2}{135}$，
$\frac{2}{135}$÷3=$\frac{2}{405}$，
此數(shù)列為：$\frac{6}{5}$，$\frac{2}{5}$，$\frac{2}{15}$，$\frac{2}{45}$，$\frac{2}{135}$，$\frac{2}{405}$．
故答案為：$\frac{2}{45}$，$\frac{2}{405}$．

點評 解答此題關鍵是找出相鄰兩個分數(shù)的倍數(shù)關系，再由此進行求解．