Question

7．计算
$\frac{2}{3}$×$\frac{3}{5}$÷$\frac{9}{25}$
$\frac{84}{169}$×13÷$8\frac{2}{5}$
42÷$\frac{7}{8}$÷$\frac{3}{4}$．

Answer 1

分析 根据分数乘除法的运算法则计算，除法要先变成乘法在计算．

解答 解：①$\frac{2}{3}$×$\frac{3}{5}$÷$\frac{9}{25}$
=$\frac{2}{3}$×$\frac{3}{5}$×$\frac{25}{9}$
=$\frac{10}{9}$

②$\frac{84}{169}$×13÷$8\frac{2}{5}$
=$\frac{84}{169}$×13×$\frac{5}{42}$
=$\frac{10}{13}$

③42÷$\frac{7}{8}$÷$\frac{3}{4}$
=42×$\frac{8}{7}$×$\frac{4}{3}$
=64

点评 此题考查分数乘除法运算顺序，认真分析数据找到正确的计算方法．