Question

8．計(jì)算下面各題．

$\frac{25}{39}$×26	$\frac{13}{42}$×3	$\frac{7}{25}$×$\frac{10}{21}$
$\frac{2}{15}$×$\frac{6}{25}$	$\frac{5}{8}$×$\frac{5}{8}$	$\frac{2}{3}$×$\frac{3}{4}$×2
$\frac{5}{21}$×14×$\frac{2}{10}$	$\frac{9}{14}$×$\frac{2}{3}$×$\frac{7}{15}$	$\frac{5}{3}$×$\frac{3}{7}$×$\frac{3}{5}$

Answer 1

分析 分?jǐn)?shù)乘法：分子相乘的積做分子，分母相乘的積做分母，能約分的先約分．

解答

解： $\frac{25}{39}$×26=$\frac{50}{3}$	$\frac{13}{42}$×3=$\frac{13}{14}$	$\frac{7}{25}$×$\frac{10}{21}$=$\frac{2}{15}$
$\frac{2}{15}$×$\frac{6}{25}$=$\frac{4}{125}$	$\frac{5}{8}$×$\frac{5}{8}$=$\frac{25}{64}$	$\frac{2}{3}$×$\frac{3}{4}$×2=1
$\frac{5}{21}$×14×$\frac{2}{10}$=$\frac{2}{3}$	$\frac{9}{14}$×$\frac{2}{3}$×$\frac{7}{15}$=$\frac{1}{5}$	$\frac{5}{3}$×$\frac{3}{7}$×$\frac{3}{5}$=$\frac{3}{7}$

點(diǎn)評(píng) 本題考查了簡(jiǎn)單的分?jǐn)?shù)乘法的計(jì)算，計(jì)算時(shí)要細(xì)心，注意把結(jié)果化成最簡(jiǎn)分?jǐn)?shù)．