Question

20．下面各題寫出必要的計(jì)算過(guò)程
$\frac{9}{10}$×$\frac{2}{3}$×$\frac{5}{6}$
$\frac{3}{8}$×4÷$\frac{3}{4}$
$\frac{9}{2}$÷$\frac{5}{2}$÷$\frac{9}{10}$．

Answer 1

分析 ①$\frac{9}{10}$×$\frac{2}{3}$×$\frac{5}{6}$根據(jù)分?jǐn)?shù)乘法計(jì)算法則進(jìn)行計(jì)算；
②$\frac{3}{8}$×4÷$\frac{3}{4}$把除法變?yōu)槌朔ê笸ㄟ^(guò)約分進(jìn)行計(jì)算；
③$\frac{9}{2}$÷$\frac{5}{2}$÷$\frac{9}{10}$把除法變?yōu)槌朔ê笸ㄟ^(guò)約分進(jìn)行計(jì)算．

解答 解：
①$\frac{9}{10}$×$\frac{2}{3}$×$\frac{5}{6}$
=$\frac{3}{5}×\frac{5}{6}$
=$\frac{1}{2}$

②$\frac{3}{8}$×4÷$\frac{3}{4}$
=$\frac{3}{8}×\frac{4}{1}×\frac{4}{3}$
=$\frac{3}{2}×\frac{4}{3}$
=2

③$\frac{9}{2}$÷$\frac{5}{2}$÷$\frac{9}{10}$
=$\frac{9}{2}×\frac{2}{5}×\frac{10}{9}$
=$\frac{9}{5}×\frac{10}{9}$
=2

點(diǎn)評(píng) 此題是考查四則混合運(yùn)算，根據(jù)分?jǐn)?shù)乘法和分?jǐn)?shù)除法計(jì)算法則進(jìn)行計(jì)算．