Question

3．比一比，看誰算得認(rèn)真，算得準(zhǔn)確．

88-55=	199+65=	0.8×0.9=	3.2÷0.4=
$\frac{7}{15}$×60=	80÷$\frac{1}{80}$=	$\frac{1}{2}$-$\frac{1}{3}$=	23.9÷8≈

Answer 1

分析 根據(jù)整數(shù)小數(shù)分?jǐn)?shù)加減乘除法的計算方法解答，23.9÷8≈24÷8．

解答 解：

88-55=33	199+65=264	0.8×0.9=0.72	3.2÷0.4=8
$\frac{7}{15}$×60=28	80÷$\frac{1}{80}$=6400	$\frac{1}{2}$-$\frac{1}{3}$=$\frac{1}{6}$	23.9÷8≈3

點(diǎn)評 口算時，注意數(shù)據(jù)特點(diǎn)和運(yùn)算符號，小數(shù)除法的估算，把小數(shù)看作整數(shù)，然后再進(jìn)一步解答．