Question

1．計(jì)算下面各題．
$\frac{4}{51}$×$\frac{3}{8}$×$\frac{17}{18}$
$\frac{22}{27}$÷$\frac{11}{5}$×$\frac{9}{10}$
$\frac{4}{5}$÷[（$\frac{3}{5}$+$\frac{1}{2}$）×2]．

Answer 1

分析 ①首先約分，然后分子分母分別相乘；
②除以一個(gè)分?jǐn)?shù)，等于乘這個(gè)分?jǐn)?shù)的倒數(shù)；然后約分，最后分子分母分別相乘；
③首先計(jì)算小括號(hào)內(nèi)的加法，然后計(jì)算中括號(hào)內(nèi)的乘法，最后計(jì)算中括號(hào)外的除法；計(jì)算得解．

解答 解：①$\frac{4}{51}$×$\frac{3}{8}$×$\frac{17}{18}$
=$\frac{1}{3}$×$\frac{1}{2}$×$\frac{1}{6}$
=$\frac{1}{36}$

②$\frac{22}{27}$÷$\frac{11}{5}$×$\frac{9}{10}$
=$\frac{22}{27}$×$\frac{5}{11}$×$\frac{9}{10}$
=$\frac{2}{3}$×$\frac{1}{1}$×$\frac{1}{2}$
=$\frac{1}{3}$

③$\frac{4}{5}$÷[（$\frac{3}{5}$+$\frac{1}{2}$）×2]
=$\frac{4}{5}$÷[$\frac{11}{10}$×2]
=$\frac{4}{5}$$÷\frac{11}{5}$
=$\frac{4}{11}$

點(diǎn)評(píng) 考查了運(yùn)算定律與簡便運(yùn)算，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)算律簡便計(jì)算．