Question

6．

口算： $\frac{5}{9}$×15=	$\frac{3}{5}$×2=	$\frac{1}{4}$×$\frac{4}{5}$=	$\frac{1}{9}$×$\frac{3}{7}$=	$\frac{7}{12}$×$\frac{3}{4}$=	$\frac{15}{17}$×$\frac{17}{15}$=
$\frac{5}{6}$×$\frac{2}{15}$=	$\frac{6}{11}$×$\frac{1}{12}$=	$\frac{3}{22}$×$\frac{11}{13}$=	$\frac{7}{6}$×24=

Answer 1

分析 根據(jù)分?jǐn)?shù)乘法的計算方法直接口算即可．

解答 解：

$\frac{5}{9}$×15=$\frac{25}{3}$	$\frac{3}{5}$×2=$\frac{6}{5}$	$\frac{1}{4}$×$\frac{4}{5}$=$\frac{1}{5}$	$\frac{1}{9}$×$\frac{3}{7}$=$\frac{1}{21}$	$\frac{7}{12}$×$\frac{3}{4}$=$\frac{7}{16}$	$\frac{15}{17}$×$\frac{17}{15}$=1
$\frac{5}{6}$×$\frac{2}{15}$=$\frac{1}{9}$	$\frac{6}{11}$×$\frac{1}{12}$=$\frac{1}{22}$	$\frac{3}{22}$×$\frac{11}{13}$=$\frac{3}{26}$	$\frac{7}{6}$×24=28

點(diǎn)評 本題考查了簡單的分?jǐn)?shù)乘法的計算，計算時要細(xì)心，注意把結(jié)果化成最簡分?jǐn)?shù)．