Question

5．口算

$\frac{3}{4}$×$\frac{1}{3}$=	$\frac{4}{5}$×$\frac{1}{2}$=	1022-982=	$\frac{1}{6}$+$\frac{5}{6}$×$\frac{1}{5}$=
50×（1+$\frac{1}{5}$）=	$\frac{3}{8}$÷$\frac{9}{16}$=	6×$\frac{1}{6}$÷6×$\frac{1}{6}$=	$\frac{1}{4}$+$\frac{1}{5}$÷$\frac{1}{5}$+$\frac{1}{4}$=
$1.25×\frac{1}{3}×8$=	$9×\frac{6}{7}+9×\frac{1}{7}$=

Answer 1

分析 根据分数四则运算的计算法则及混合运算的顺序计算即可，6×$\frac{1}{6}$÷6×$\frac{1}{6}$、$1.25×\frac{1}{3}×8$运用乘法交换律简算，$9×\frac{6}{7}+9×\frac{1}{7}$运用乘法分配律简算．

解答 解：

$\frac{3}{4}$×$\frac{1}{3}$=$\frac{1}{4}$	$\frac{4}{5}$×$\frac{1}{2}$=$\frac{2}{5}$	1022-982=800	$\frac{1}{6}$+$\frac{5}{6}$×$\frac{1}{5}$=$\frac{1}{3}$
50×（1+$\frac{1}{5}$）=60	$\frac{3}{8}$÷$\frac{9}{16}$=$\frac{2}{3}$	6×$\frac{1}{6}$÷6×$\frac{1}{6}$=$\frac{1}{36}$	$\frac{1}{4}$+$\frac{1}{5}$÷$\frac{1}{5}$+$\frac{1}{4}$=1.5
$1.25×\frac{1}{3}×8$=$\frac{10}{3}$	$9×\frac{6}{7}+9×\frac{1}{7}$=9

点评 此题考查了分数四则运算，要注意有括号的先算括号里的．