Question

2．直接寫(xiě)得數(shù)．

$\frac{2}{5}$×$\frac{15}{4}$=	$\frac{4}{17}$×34=	$\frac{8}{21}$×$\frac{7}{16}$=	$\frac{1}{20}$×$\frac{2}{3}$=	$\frac{4}{7}$×$\frac{3}{8}$=
$\frac{13}{15}$×30=	28×$\frac{7}{24}$=	$\frac{5}{9}$×15=

Answer 1

分析 根據(jù)分?jǐn)?shù)乘法的計(jì)算方法：用分子相乘的積作分子，分母相乘的積作分母，能約分的要約分；由此依次進(jìn)行計(jì)算即可．

解答 解：

$\frac{2}{5}$×$\frac{15}{4}$=$\frac{3}{2}$	$\frac{4}{17}$×34=8	$\frac{8}{21}$×$\frac{7}{16}$=$\frac{1}{6}$	$\frac{1}{20}$×$\frac{2}{3}$=$\frac{1}{30}$	$\frac{4}{7}$×$\frac{3}{8}$=$\frac{3}{14}$
$\frac{13}{15}$×30=26	28×$\frac{7}{24}$=$\frac{49}{6}$	$\frac{5}{9}$×15=$\frac{25}{3}$

點(diǎn)評(píng) 明確分?jǐn)?shù)乘法的計(jì)算法則，是解答此題的關(guān)鍵．