Question

3．直接寫得數(shù)

$\frac{2}{5}$×$\frac{3}{4}$=	12-$\frac{11}{5}$=
$\frac{1}{5}$-$\frac{1}{6}$=	$\frac{20}{39}$×$\frac{13}{15}$=
0.1÷$\frac{3}{30}$=	16÷$\frac{4}{17}$=
1$\frac{2}{3}$+0.5=	1÷0.1=
$\frac{7}{8}$-0.75=	$\frac{5}{21}$÷$\frac{1}{5}$=
（$\frac{7}{8}$+$\frac{3}{4}$）×8=	99×0.25+0.25=
7.28-3.8-2.2=	$\frac{1}{8}$×$\frac{1}{8}$÷$\frac{1}{8}$×$\frac{1}{8}$=

Answer 1

分析 運(yùn)用分?jǐn)?shù)加減及分?jǐn)?shù)、小數(shù)的乘除法的計(jì)算法則進(jìn)行計(jì)算即可，計(jì)算99×0.25+0.25與（$\frac{7}{8}$+$\frac{3}{4}$）×8運(yùn)用乘法的分配律進(jìn)行計(jì)算，計(jì)算 7.28-3.8-2.2運(yùn)用減法的性質(zhì)．

解答 解：

$\frac{2}{5}$×$\frac{3}{4}$=0.3	12-$\frac{11}{5}$=9.8
$\frac{1}{5}$-$\frac{1}{6}$=$\frac{1}{30}$	$\frac{20}{39}$×$\frac{13}{15}$=$\frac{4}{9}$
0.1÷$\frac{3}{30}$=1	16÷$\frac{4}{17}$=68
1$\frac{2}{3}$+0.5=2$\frac{1}{6}$	1÷0.1=10
$\frac{7}{8}$-0.75=0.125	$\frac{5}{21}$÷$\frac{1}{5}$=1$\frac{4}{21}$
（$\frac{7}{8}$+$\frac{3}{4}$）×8=13	99×0.25+0.25=25
7.28-3.8-2.2=1.28	$\frac{1}{8}$×$\frac{1}{8}$÷$\frac{1}{8}$×$\frac{1}{8}$=$\frac{1}{64}$

點(diǎn)評 本題考查了分?jǐn)?shù)、小數(shù)的四則混合運(yùn)算計(jì)算法則，注意計(jì)算結(jié)果要化簡．