Question

14．計(jì)算

$\frac{23}{24}$×$\frac{8}{69}$×$\frac{5}{4}$	$\frac{15}{16}$×$\frac{20}{21}$×$\frac{1}{5}$	$\frac{9}{10}$×$\frac{2}{3}$×$\frac{5}{6}$
20×$\frac{5}{6}$×$\frac{3}{4}$	$\frac{2}{5}$×$\frac{5}{6}$×$\frac{3}{8}$	$\frac{2}{7}$×14×$\frac{5}{8}$

Answer 1

分析 根據(jù)分?jǐn)?shù)乘法的計(jì)算方法進(jìn)行計(jì)算，能約分的要先約分，再進(jìn)行計(jì)算．

解答 解：（1）$\frac{23}{24}$×$\frac{8}{69}$×$\frac{5}{4}$
=$\frac{1}{9}×\frac{5}{4}$
=$\frac{5}{36}$；

（2）$\frac{15}{16}$×$\frac{20}{21}$×$\frac{1}{5}$
=$\frac{25}{28}$×$\frac{1}{5}$
=$\frac{5}{28}$；

（3）$\frac{9}{10}$×$\frac{2}{3}$×$\frac{5}{6}$
=$\frac{3}{5}×\frac{5}{6}$
=$\frac{1}{2}$；

（4）20×$\frac{5}{6}$×$\frac{3}{4}$
=10×$\frac{5}{3}×\frac{3}{4}$
=$\frac{25}{2}$；

（5）$\frac{2}{5}$×$\frac{5}{6}$×$\frac{3}{8}$
=$\frac{1}{3}×\frac{3}{8}$
=$\frac{1}{8}$；

（6）$\frac{2}{7}$×14×$\frac{5}{8}$
=4×$\frac{5}{8}$
=$\frac{5}{2}$．

點(diǎn)評(píng) 本題主要考查了學(xué)生對(duì)分?jǐn)?shù)乘法計(jì)算方法的掌握，最后的結(jié)果一定要化成最簡(jiǎn)分?jǐn)?shù)．