Question

8．计算下面各题．

$\frac{25}{39}$×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 分数乘法：分子相乘的积做分子，分母相乘的积做分母，能约分的先约分．

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×$\frac{2}{10}$=$\frac{2}{3}$	$\frac{9}{14}$×$\frac{2}{3}$×$\frac{7}{15}$=$\frac{1}{5}$	$\frac{5}{3}$×$\frac{3}{7}$×$\frac{3}{5}$=$\frac{3}{7}$

点评 本题考查了简单的分数乘法的计算，计算时要细心，注意把结果化成最简分数．