Question

12．直接寫出得數(shù)．

$\frac{3}{8}$÷0.125=	4-0.25×4=	3×$\frac{1}{3}$×$\frac{1}{3}$=	40×25%=
4.3×101=	（8+0.8）×1.25=	$\frac{6}{7}$×$\frac{3}{5}$÷$\frac{6}{7}$×$\frac{3}{5}$=	0.9+99×0.9=
$\frac{2}{5}$×2.5=	9981÷49≈

Answer 1

分析 根據(jù)分?jǐn)?shù)和小數(shù)加減乘除法的計(jì)算方法進(jìn)行計(jì)算．
4.3×101、（8+0.8）×1.25、0.9+99×0.9根據(jù)乘法分配律進(jìn)行簡(jiǎn)算．

解答 解：

$\frac{3}{8}$÷0.125=3	4-0.25×4=3	3×$\frac{1}{3}$×$\frac{1}{3}$=$\frac{1}{3}$	40×25%=10
4.3×101=434.3	（8+0.8）×1.25=11	$\frac{6}{7}$×$\frac{3}{5}$÷$\frac{6}{7}$×$\frac{3}{5}$=$\frac{9}{25}$	0.9+99×0.9=90
$\frac{2}{5}$×2.5=1	9981÷49≈200

點(diǎn)評(píng) 口算時(shí)，注意運(yùn)算符號(hào)和數(shù)據(jù)，然后再進(jìn)一步計(jì)算．