Question

20．直接寫得數(shù)．

$\frac{2}{3}$×$\frac{9}{10}$=	1.8×$\frac{1}{6}$=	$\frac{7}{12}$×$\frac{3}{14}$=	$\frac{1}{6}$+$\frac{6}{10}$=
$\frac{4}{5}$×0=	$\frac{11}{15}$×$\frac{3}{22}$=	$\frac{2}{5}$×2=	$\frac{1}{6}$+$\frac{5}{6}$×$\frac{1}{5}$=

Answer 1

分析 ①②③⑥約分計(jì)算；④通分計(jì)算；⑤0乘任何數(shù)都得0；⑦用整數(shù)與分子相乘的積做分子，分母不變；⑧先算乘法，再算加法．

解答 解：

$\frac{2}{3}$×$\frac{9}{10}$=$\frac{3}{5}$	1.8×$\frac{1}{6}$=0.3	$\frac{7}{12}$×$\frac{3}{14}$=$\frac{1}{8}$	$\frac{1}{6}$+$\frac{6}{10}$=$\frac{23}{30}$
$\frac{4}{5}$×0=0	$\frac{11}{15}$×$\frac{3}{22}$=$\frac{1}{10}$	$\frac{2}{5}$×2=$\frac{4}{5}$	$\frac{1}{6}$+$\frac{5}{6}$×$\frac{1}{5}$=$\frac{1}{3}$

點(diǎn)評(píng) 此題考查的目的是理解掌握分?jǐn)?shù)四則運(yùn)算的計(jì)算法則，并且能夠正確熟練地進(jìn)行口算，提高口算能力．