1. $\frac{2}{3} ÷ \frac{4}{5} × \frac{9}{10} = \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} =$
$\frac{5}{2} ÷ 3 ÷ \frac{5}{6} = \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} =$
$\frac{4}{7} × \frac{21}{10} ÷ \frac{3}{5} = \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} =$
$\frac{5}{2} ÷ 3 ÷ \frac{5}{6} = \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} =$
$\frac{4}{7} × \frac{21}{10} ÷ \frac{3}{5} = \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} × \frac{(\quad)}{(\quad)} =$
答案
$1. \frac{2}{3},\frac{5}{4},\frac{9}{10},\frac{3}{4};\frac{5}{2},\frac{1}{3},\frac{6}{5},1;\frac{4}{7},\frac{21}{10},\frac{5}{3},2$
解析
$\frac{2}{3} ÷ \frac{4}{5} × \frac{9}{10} = \frac{2}{3} × \frac{5}{4} × \frac{9}{10} = \frac{3}{4}$
$\frac{5}{2} ÷ 3 ÷ \frac{5}{6} = \frac{5}{2} × \frac{1}{3} × \frac{6}{5} = 1$
$\frac{4}{7} × \frac{21}{10} ÷ \frac{3}{5} = \frac{4}{7} × \frac{21}{10} × \frac{5}{3} = 2$
$\frac{5}{2} ÷ 3 ÷ \frac{5}{6} = \frac{5}{2} × \frac{1}{3} × \frac{6}{5} = 1$
$\frac{4}{7} × \frac{21}{10} ÷ \frac{3}{5} = \frac{4}{7} × \frac{21}{10} × \frac{5}{3} = 2$
2. $\frac{3}{4} ÷ 15 ÷ \frac{6}{5}$ $\frac{2}{5} ÷ \frac{1}{5} × \frac{1}{6}$
$\frac{6}{5} × \frac{2}{3} ÷ \frac{8}{15}$ $\frac{9}{10} ÷ \frac{3}{8} ÷ \frac{1}{5}$
$\frac{6}{5} × \frac{2}{3} ÷ \frac{8}{15}$ $\frac{9}{10} ÷ \frac{3}{8} ÷ \frac{1}{5}$
答案
$2. \frac{1}{24},\frac{1}{3},\frac{3}{2},12$
解析
$\frac{3}{4} ÷ 15 ÷ \frac{6}{5} = \frac{3}{4} × \frac{1}{15} × \frac{5}{6} = \frac{1}{24}$
$\frac{2}{5} ÷ \frac{1}{5} × \frac{1}{6} = \frac{2}{5} × 5 × \frac{1}{6} = \frac{1}{3}$
$\frac{6}{5} × \frac{2}{3} ÷ \frac{8}{15} = \frac{6}{5} × \frac{2}{3} × \frac{15}{8} = \frac{3}{2}$
$\frac{9}{10} ÷ \frac{3}{8} ÷ \frac{1}{5} = \frac{9}{10} × \frac{8}{3} × 5 = 12$
$\frac{2}{5} ÷ \frac{1}{5} × \frac{1}{6} = \frac{2}{5} × 5 × \frac{1}{6} = \frac{1}{3}$
$\frac{6}{5} × \frac{2}{3} ÷ \frac{8}{15} = \frac{6}{5} × \frac{2}{3} × \frac{15}{8} = \frac{3}{2}$
$\frac{9}{10} ÷ \frac{3}{8} ÷ \frac{1}{5} = \frac{9}{10} × \frac{8}{3} × 5 = 12$
3. 一个三角形的底是$\frac{3}{2}$米,高是$\frac{4}{9}$米。它的面积是多少平方米?
答案
$3. \frac{3}{2} × \frac{4}{9} ÷ 2 = \frac{1}{3}($平方米)
4. 一辆汽车$\frac{4}{3}$小时行驶 120 千米。照这样计算,这辆汽车$\frac{8}{5}$小时行驶多少千米?
答案
$4. 120 ÷ \frac{4}{3} × \frac{8}{5} = 144($千米)
5. 一堆货物有$\frac{5}{2}$吨,2 台拖拉机$\frac{5}{4}$小时可以运完。平均每台拖拉机每小时运多少吨?
答案
$5. \frac{5}{2} ÷ 2 ÷ \frac{5}{4} = 1($吨)
解析
$\frac{5}{2} ÷ 2 ÷ \frac{5}{4} = 1$(吨)
6. 小李家的住房面积是 108 平方米,客厅面积占住房面积的$\frac{2}{9}$,客厅面积是厨房面积的$\frac{8}{3}$。厨房面积是多少平方米?
答案
6. 先根据“客厅面积占住房面积的$\frac{2}{9}”$求出客厅面积,再根据“客厅面积是厨房面积的$\frac{8}{3}”$求出厨房面积。$108 × \frac{2}{9} ÷ \frac{8}{3} = 9($平方米)。
解析
$108×\frac{2}{9}÷\frac{8}{3}=9$(平方米)
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