Question

20．直接寫出得數(shù)．

$\frac{2}{4}$+$\frac{1}{4}$=	10÷$\frac{2}{5}$=	$\frac{3}{5}$÷$\frac{9}{10}$=	1÷$\frac{7}{8}$=	$\frac{2}{3}$×$\frac{3}{10}$=
$\frac{3}{4}$×$\frac{2}{5}$×$\frac{4}{3}$=	8×$\frac{3}{8}$+8×$\frac{1}{8}$=	55×$\frac{1}{8}$÷$\frac{1}{8}$=	$\frac{1}{2}$×$\frac{1}{3}$÷$\frac{1}{2}$×$\frac{1}{3}$=	0×$\frac{7}{12}$+$\frac{1}{8}$=

Answer 1

分析 根據(jù)分?jǐn)?shù)加減乘除法的計(jì)算方法進(jìn)行計(jì)算．
$\frac{3}{4}$×$\frac{2}{5}$×$\frac{4}{3}$根據(jù)乘法交換律進(jìn)行簡算；
8×$\frac{3}{8}$+8×$\frac{1}{8}$根據(jù)乘法分配律進(jìn)行簡算．

解答 解：

$\frac{2}{4}$+$\frac{1}{4}$=$\frac{3}{4}$	10÷$\frac{2}{5}$=25	$\frac{3}{5}$÷$\frac{9}{10}$=$\frac{2}{3}$	1÷$\frac{7}{8}$=$\frac{8}{7}$	$\frac{2}{3}$×$\frac{3}{10}$=$\frac{1}{5}$
$\frac{3}{4}$×$\frac{2}{5}$×$\frac{4}{3}$=$\frac{2}{5}$	8×$\frac{3}{8}$+8×$\frac{1}{8}$=4	55×$\frac{1}{8}$÷$\frac{1}{8}$=55	$\frac{1}{2}$×$\frac{1}{3}$÷$\frac{1}{2}$×$\frac{1}{3}$=$\frac{1}{9}$	0×$\frac{7}{12}$+$\frac{1}{8}$=$\frac{1}{8}$

點(diǎn)評 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．