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1. 求比值。
0.25:4 $\frac{2}{5}:1\frac{2}{3}$
0.25:4 $\frac{2}{5}:1\frac{2}{3}$
答案
$\frac{1}{16}$ $\frac{6}{25}$
解析
$0.25:4=\frac{1}{4}:4=\frac{1}{4}÷4=\frac{1}{16} $
$\frac{2}{5}:1\frac{2}{3}=\frac{2}{5}:\frac{5}{3}=\frac{2}{5}÷\frac{5}{3}=\frac{6}{25} $
$\frac{2}{5}:1\frac{2}{3}=\frac{2}{5}:\frac{5}{3}=\frac{2}{5}÷\frac{5}{3}=\frac{6}{25} $
2. 化简比。
20 分:2 时 0.75:$\frac{3}{5}$
20 分:2 时 0.75:$\frac{3}{5}$
答案
1:6 5:4
3. 口算。
10÷10%=
10÷10%=
100
$\frac{3}{16}×\frac{4}{9}=$$\frac{1}{12}$
$\frac{5}{6}÷\frac{2}{3}×0=$0
$\frac{3}{4}×\frac{1}{2}÷\frac{3}{4}×\frac{1}{2}=$$\frac{1}{4}$
答案
100 $\frac{1}{12}$ 0 $\frac{1}{4}$
4. 能简算的要简算。
$(\frac{4}{9}-\frac{1}{6})÷\frac{3}{5}$ $18÷\frac{3}{10}×\frac{4}{3}$ $48×(\frac{7}{12}+\frac{5}{16})$ $\frac{36}{5}×\frac{9}{4}÷\frac{3}{4}$
$24÷(\frac{1}{2}-\frac{1}{3})$ $\frac{11}{9}×\frac{5}{14}-\frac{5}{14}×\frac{2}{9}$ $(\frac{21}{5}+\frac{21}{8})÷(\frac{3}{5}+\frac{3}{8})$
$(\frac{4}{9}-\frac{1}{6})÷\frac{3}{5}$ $18÷\frac{3}{10}×\frac{4}{3}$ $48×(\frac{7}{12}+\frac{5}{16})$ $\frac{36}{5}×\frac{9}{4}÷\frac{3}{4}$
$24÷(\frac{1}{2}-\frac{1}{3})$ $\frac{11}{9}×\frac{5}{14}-\frac{5}{14}×\frac{2}{9}$ $(\frac{21}{5}+\frac{21}{8})÷(\frac{3}{5}+\frac{3}{8})$
答案
$\frac{25}{54}$ 80 43 $\frac{108}{5}$ 144 $\frac{5}{14}$ 7
解析
$(\frac{4}{9}-\frac{1}{6})÷\frac{3}{5}$
$=(\frac{8}{18}-\frac{3}{18})×\frac{5}{3}$
$=\frac{5}{18}×\frac{5}{3}$
$=\frac{25}{54}$
$18÷\frac{3}{10}×\frac{4}{3}$
$=18×\frac{10}{3}×\frac{4}{3}$
$=60×\frac{4}{3}$
$=80$
$48×(\frac{7}{12}+\frac{5}{16})$
$=48×\frac{7}{12}+48×\frac{5}{16}$
$=28 + 15$
$=43$
$\frac{36}{5}×\frac{9}{4}÷\frac{3}{4}$
$=\frac{36}{5}×\frac{9}{4}×\frac{4}{3}$
$=\frac{36}{5}×3$
$=\frac{108}{5}$
$24÷(\frac{1}{2}-\frac{1}{3})$
$=24÷(\frac{3}{6}-\frac{2}{6})$
$=24÷\frac{1}{6}$
$=24×6$
$=144$
$\frac{11}{9}×\frac{5}{14}-\frac{5}{14}×\frac{2}{9}$
$=\frac{5}{14}×(\frac{11}{9}-\frac{2}{9})$
$=\frac{5}{14}×1$
$=\frac{5}{14}$
$(\frac{21}{5}+\frac{21}{8})÷(\frac{3}{5}+\frac{3}{8})$
$=21×(\frac{1}{5}+\frac{1}{8})÷[3×(\frac{1}{5}+\frac{1}{8})]$
$=21÷3$
$=7$
$=(\frac{8}{18}-\frac{3}{18})×\frac{5}{3}$
$=\frac{5}{18}×\frac{5}{3}$
$=\frac{25}{54}$
$18÷\frac{3}{10}×\frac{4}{3}$
$=18×\frac{10}{3}×\frac{4}{3}$
$=60×\frac{4}{3}$
$=80$
$48×(\frac{7}{12}+\frac{5}{16})$
$=48×\frac{7}{12}+48×\frac{5}{16}$
$=28 + 15$
$=43$
$\frac{36}{5}×\frac{9}{4}÷\frac{3}{4}$
$=\frac{36}{5}×\frac{9}{4}×\frac{4}{3}$
$=\frac{36}{5}×3$
$=\frac{108}{5}$
$24÷(\frac{1}{2}-\frac{1}{3})$
$=24÷(\frac{3}{6}-\frac{2}{6})$
$=24÷\frac{1}{6}$
$=24×6$
$=144$
$\frac{11}{9}×\frac{5}{14}-\frac{5}{14}×\frac{2}{9}$
$=\frac{5}{14}×(\frac{11}{9}-\frac{2}{9})$
$=\frac{5}{14}×1$
$=\frac{5}{14}$
$(\frac{21}{5}+\frac{21}{8})÷(\frac{3}{5}+\frac{3}{8})$
$=21×(\frac{1}{5}+\frac{1}{8})÷[3×(\frac{1}{5}+\frac{1}{8})]$
$=21÷3$
$=7$
5. 解方程。
$x - 35\%x = 26$ $\frac{1}{3}x + \frac{1}{4} = \frac{2}{3}$ $(x + \frac{2}{5})×15 = 45$
$x - 35\%x = 26$ $\frac{1}{3}x + \frac{1}{4} = \frac{2}{3}$ $(x + \frac{2}{5})×15 = 45$
答案
x=40 x=$\frac{5}{4}$ x=2$\frac{3}{5}$
解析
解：
$x - 35\%x = 26$
$0.65x = 26$
$x = 26 ÷ 0.65$
$x = 40$
$\frac{1}{3}x + \frac{1}{4} = \frac{2}{3}$
$\frac{1}{3}x = \frac{2}{3} - \frac{1}{4}$
$\frac{1}{3}x = \frac{8}{12} - \frac{3}{12}$
$\frac{1}{3}x = \frac{5}{12}$
$x = \frac{5}{12} × 3$
$x = \frac{5}{4}$
$(x + \frac{2}{5})×15 = 45$
$x + \frac{2}{5} = 45 ÷ 15$
$x + \frac{2}{5} = 3$
$x = 3 - \frac{2}{5}$
$x = \frac{15}{5} - \frac{2}{5}$
$x = \frac{13}{5} = 2\frac{3}{5}$
$x - 35\%x = 26$
$0.65x = 26$
$x = 26 ÷ 0.65$
$x = 40$
$\frac{1}{3}x + \frac{1}{4} = \frac{2}{3}$
$\frac{1}{3}x = \frac{2}{3} - \frac{1}{4}$
$\frac{1}{3}x = \frac{8}{12} - \frac{3}{12}$
$\frac{1}{3}x = \frac{5}{12}$
$x = \frac{5}{12} × 3$
$x = \frac{5}{4}$
$(x + \frac{2}{5})×15 = 45$
$x + \frac{2}{5} = 45 ÷ 15$
$x + \frac{2}{5} = 3$
$x = 3 - \frac{2}{5}$
$x = \frac{15}{5} - \frac{2}{5}$
$x = \frac{13}{5} = 2\frac{3}{5}$
