Question

10．脫式計(jì)算
$\frac{6}{7}$×21×$\frac{2}{3}$
$\frac{5}{9}$×$\frac{6}{25}$×$\frac{9}{4}$
$\frac{3}{11}$×$\frac{9}{5}$×$\frac{11}{25}$．

Answer 1

分析 （1）按照從左到右的順序計(jì)算；
（2）（3）根據(jù)乘法交換律簡(jiǎn)算．

解答 解：（1）$\frac{6}{7}$×21×$\frac{2}{3}$
=18×$\frac{2}{3}$
=12

（2）$\frac{5}{9}$×$\frac{6}{25}$×$\frac{9}{4}$
=$\frac{5}{9}$×$\frac{9}{4}$×$\frac{6}{25}$
=$\frac{5}{4}$×$\frac{6}{25}$
=$\frac{3}{10}$

（3）$\frac{3}{11}$×$\frac{9}{5}$×$\frac{11}{25}$
=$\frac{3}{11}$×$\frac{11}{25}$×$\frac{9}{5}$
=$\frac{3}{25}$×$\frac{9}{5}$
=$\frac{27}{125}$

點(diǎn)評(píng) 本題考查了四則混合運(yùn)算，注意運(yùn)算順序和運(yùn)算法則，靈活運(yùn)用所學(xué)的運(yùn)算定律進(jìn)行簡(jiǎn)便計(jì)算．