Question

9．計(jì)算．
[0.875-（$\frac{7}{12}$+$\frac{4}{15}$）]÷$\frac{5}{16}$
$\frac{7}{2}$÷〔（$\frac{7}{20}$+75%）×$\frac{5}{11}$〕
$\frac{9}{5}$-〔1÷（$\frac{3}{4}$-$\frac{1}{3}$）〕×$\frac{25}{36}$
19.2÷〔3.2×（1-$\frac{5}{8}$）+3.6〕

Answer 1

分析 本題根據(jù)四則混合運(yùn)算的運(yùn)算順序計(jì)算即可：先算乘除，再算加減，有括號(hào)的要先算括號(hào)里面的．

解答 解：①[0.875-（$\frac{7}{12}$+$\frac{4}{15}$）]÷$\frac{5}{16}$
=[0.875-$\frac{51}{60}$]÷$\frac{5}{16}$
=$\frac{1}{40}$÷$\frac{5}{16}$
=$\frac{2}{25}$

②$\frac{7}{2}$÷〔（$\frac{7}{20}$+75%）×$\frac{5}{11}$〕
=$\frac{7}{2}$÷〔（$\frac{11}{10}$×$\frac{5}{11}$〕
=$\frac{7}{2}÷\frac{1}{2}$
=7

③$\frac{9}{5}$-〔1÷（$\frac{3}{4}$-$\frac{1}{3}$）〕×$\frac{25}{36}$
=$\frac{9}{5}$-〔1÷$\frac{5}{12}$〕×$\frac{25}{36}$
=$\frac{9}{5}$-$\frac{12}{5}$×$\frac{25}{36}$
=$\frac{9}{5}-\frac{5}{3}$
=$\frac{2}{15}$

④19.2÷〔3.2×（1-$\frac{5}{8}$）+3.6〕
=19.2÷〔3.2×$\frac{3}{8}$+3.6〕
=19.2÷〔1.2+3.6〕
=19.2÷4.8
=4

點(diǎn)評(píng) 本題中數(shù)據(jù)較為復(fù)雜，完成時(shí)要細(xì)心，注意小數(shù)、分?jǐn)?shù)之間的互化及通分約分．