Question

3．计算：
①$\frac{7}{20}$×$\frac{3}{4}$×$\frac{5}{7}$
②$\frac{8}{9}$×$\frac{3}{25}$×$\frac{5}{12}$
③$\frac{5}{17}$×34×$\frac{1}{15}$．

Answer 1

分析 根据分数乘法法则计算即可．

解答 解：①$\frac{7}{20}$×$\frac{3}{4}$×$\frac{5}{7}$
=$\frac{7}{20}$×$\frac{5}{7}$×$\frac{3}{4}$
=$\frac{1}{4}$×$\frac{3}{4}$
=$\frac{3}{16}$

②$\frac{8}{9}$×$\frac{3}{25}$×$\frac{5}{12}$
=$\frac{8}{3}$×$\frac{1}{25}$×$\frac{5}{12}$
=$\frac{1}{5}$×$\frac{2}{9}$
=$\frac{2}{45}$

③$\frac{5}{17}$×34×$\frac{1}{15}$
=10×$\frac{1}{15}$
=$\frac{2}{3}$

点评 解答本题要注意结果应是最简分数．