Question

13．脱式计算：
$\frac{5}{14}$×$\frac{1}{10}$×$\frac{7}{6}$            
$\frac{7}{15}$÷$\frac{8}{25}$÷$\frac{5}{24}$         
 $\frac{10}{21}$÷$\frac{5}{3}$×$\frac{3}{5}$．

Answer 1

分析 把有除法的先改为乘法，再进一步约分计算即可．

解答 解：$\frac{5}{14}$×$\frac{1}{10}$×$\frac{7}{6}$
=$\frac{1}{28}$×$\frac{7}{6}$
=$\frac{1}{24}$

$\frac{7}{15}$÷$\frac{8}{25}$÷$\frac{5}{24}$
=$\frac{7}{15}$×$\frac{25}{8}$×$\frac{24}{5}$
=$\frac{35}{24}$×$\frac{24}{5}$
=7

$\frac{10}{21}$×$\frac{3}{5}$×$\frac{3}{5}$
=$\frac{2}{7}$×$\frac{3}{5}$
=$\frac{6}{35}$

点评 分数四则计算的关键是抓住运算顺序，正确按运算顺序计算即可．