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一、口算。
$ \frac{8}{7} × 0.125 = $
$ \frac{9}{2} × \frac{2}{3} = $
$ 60 × \frac{4}{15} = $
$ \frac{8}{5} × \frac{8}{5} = $
$ \frac{2}{3} - \frac{1}{2} = $
$ \frac{3}{8} + \frac{7}{2} = $
$ \frac{3}{4} × \frac{5}{6} = $
$ 1 - \frac{5}{7} = $
$ \frac{2}{3} × \frac{7}{2} = $
$ \frac{2}{3} + \frac{3}{2} = $
$ \frac{13}{8} × \frac{4}{39} = $
$ \frac{5}{3} × \frac{3}{5} = $
$ \frac{11}{2} + \frac{5}{4} = $
$ \frac{5}{8} + \frac{1}{4} = $
$ \frac{11}{5} × \frac{10}{11} = $
$ \frac{2}{21} × \frac{7}{4} = $
$ 28 × \frac{2}{21} = $
$ \frac{7}{6} × \frac{3}{5} = $
$ \frac{4}{3} × \frac{15}{16} = $
$ \frac{16}{25} × \frac{5}{24} = $
$ \frac{5}{6} - \frac{7}{20} = $
$ \frac{8}{7} × 0.125 = $
$\frac{1}{7}$
$ \frac{9}{2} × \frac{2}{3} = $
3
$ 60 × \frac{4}{15} = $
16
$ \frac{8}{5} × \frac{8}{5} = $
$\frac{64}{25}$
$ \frac{2}{3} - \frac{1}{2} = $
$\frac{1}{6}$
$ \frac{3}{8} + \frac{7}{2} = $
$\frac{31}{8}$
$ \frac{3}{4} × \frac{5}{6} = $
$\frac{5}{8}$
$ 1 - \frac{5}{7} = $
$\frac{2}{7}$
$ \frac{2}{3} × \frac{7}{2} = $
$\frac{7}{3}$
$ \frac{2}{3} + \frac{3}{2} = $
$\frac{13}{6}$
$ \frac{13}{8} × \frac{4}{39} = $
$\frac{1}{6}$
$ \frac{5}{3} × \frac{3}{5} = $
1
$ \frac{11}{2} + \frac{5}{4} = $
$\frac{27}{4}$
$ \frac{5}{8} + \frac{1}{4} = $
$\frac{7}{8}$
$ \frac{11}{5} × \frac{10}{11} = $
2
$ \frac{2}{21} × \frac{7}{4} = $
$\frac{1}{6}$
$ 28 × \frac{2}{21} = $
$\frac{8}{3}$
$ \frac{7}{6} × \frac{3}{5} = $
$\frac{7}{10}$
$ \frac{4}{3} × \frac{15}{16} = $
$\frac{5}{4}$
$ \frac{16}{25} × \frac{5}{24} = $
$\frac{2}{15}$
$ \frac{5}{6} - \frac{7}{20} = $
$\frac{29}{60}$
答案
一、$\frac{1}{7}$ 3 16
$\frac{64}{25}$ $\frac{1}{6}$ $\frac{31}{8}$
$\frac{5}{8}$ $\frac{2}{7}$ $\frac{7}{3}$
$\frac{13}{6}$ $\frac{1}{6}$ 1
$\frac{27}{4}$ $\frac{7}{8}$ 2
$\frac{1}{6}$ $\frac{8}{3}$ $\frac{7}{10}$
$\frac{5}{4}$ $\frac{2}{15}$ $\frac{29}{60}$
$\frac{64}{25}$ $\frac{1}{6}$ $\frac{31}{8}$
$\frac{5}{8}$ $\frac{2}{7}$ $\frac{7}{3}$
$\frac{13}{6}$ $\frac{1}{6}$ 1
$\frac{27}{4}$ $\frac{7}{8}$ 2
$\frac{1}{6}$ $\frac{8}{3}$ $\frac{7}{10}$
$\frac{5}{4}$ $\frac{2}{15}$ $\frac{29}{60}$
二、计算下面各题。
$ \frac{1}{5} × \frac{10}{39} × \frac{13}{8} $
$ \frac{15}{16} × \frac{4}{25} × \frac{20}{3} $
$ \frac{4}{9} × 36 × \frac{5}{8} $
$ \frac{10}{51} × \frac{6}{7} × \frac{34}{25} $
$ \frac{3}{10} × \frac{5}{6} × \frac{3}{5} $
$ \frac{9}{10} × \frac{4}{5} × 3 $
$ \frac{1}{5} × \frac{10}{39} × \frac{13}{8} $
$ \frac{15}{16} × \frac{4}{25} × \frac{20}{3} $
$ \frac{4}{9} × 36 × \frac{5}{8} $
$ \frac{10}{51} × \frac{6}{7} × \frac{34}{25} $
$ \frac{3}{10} × \frac{5}{6} × \frac{3}{5} $
$ \frac{9}{10} × \frac{4}{5} × 3 $
答案
1. 计算$\frac{1}{5}×\frac{10}{39}×\frac{13}{8}$：
解：
$\frac{1}{5}×\frac{10}{39}×\frac{13}{8}=\frac{1×10×13}{5×39×8}$
约分：$10÷5 = 2$，$13÷13 = 1$，$39÷13 = 3$
则$\frac{1×2×1}{1×3×8}=\frac{2}{24}=\frac{1}{12}$
2. 计算$\frac{15}{16}×\frac{4}{25}×\frac{20}{3}$：
解：
$\frac{15}{16}×\frac{4}{25}×\frac{20}{3}=\frac{15×4×20}{16×25×3}$
约分：$15÷3 = 5$，$4÷4 = 1$，$16÷4 = 4$，$20÷5 = 4$，$25÷5 = 5$
则$\frac{5×1×4}{4×5×1}=1$
3. 计算$\frac{4}{9}×36×\frac{5}{8}$：
解：
$\frac{4}{9}×36×\frac{5}{8}=\frac{4×36×5}{9×8}$
约分：$36÷9 = 4$，$4÷4 = 1$，$8÷4 = 2$
则$\frac{1×4×5}{1×2}=10$
4. 计算$\frac{10}{51}×\frac{6}{7}×\frac{34}{25}$：
解：
$\frac{10}{51}×\frac{6}{7}×\frac{34}{25}=\frac{10×6×34}{51×7×25}$
约分：$10÷5 = 2$，$51÷17 = 3$，$34÷17 = 2$，$25÷5 = 5$
则$\frac{2×6×2}{3×7×5}=\frac{24}{105}=\frac{8}{35}$
5. 计算$\frac{3}{10}×\frac{5}{6}×\frac{3}{5}$：
解：
$\frac{3}{10}×\frac{5}{6}×\frac{3}{5}=\frac{3×5×3}{10×6×5}$
约分：$5÷5 = 1$，$10÷5 = 2$，$3÷3 = 1$，$6÷3 = 2$
则$\frac{1×1×3}{2×2×1}=\frac{3}{4}$
6. 计算$\frac{9}{10}×\frac{4}{5}×3$：
解：
$\frac{9}{10}×\frac{4}{5}×3=\frac{9×4×3}{10×5}$
计算：$9×4×3 = 108$，$10×5 = 50$
则$\frac{108}{50}=\frac{54}{25}$
综上，答案依次为$\frac{1}{12}$；$1$；$10$；$\frac{8}{35}$；$\frac{3}{4}$；$\frac{54}{25}$。
解：
$\frac{1}{5}×\frac{10}{39}×\frac{13}{8}=\frac{1×10×13}{5×39×8}$
约分：$10÷5 = 2$，$13÷13 = 1$，$39÷13 = 3$
则$\frac{1×2×1}{1×3×8}=\frac{2}{24}=\frac{1}{12}$
2. 计算$\frac{15}{16}×\frac{4}{25}×\frac{20}{3}$：
解：
$\frac{15}{16}×\frac{4}{25}×\frac{20}{3}=\frac{15×4×20}{16×25×3}$
约分：$15÷3 = 5$，$4÷4 = 1$，$16÷4 = 4$，$20÷5 = 4$，$25÷5 = 5$
则$\frac{5×1×4}{4×5×1}=1$
3. 计算$\frac{4}{9}×36×\frac{5}{8}$：
解：
$\frac{4}{9}×36×\frac{5}{8}=\frac{4×36×5}{9×8}$
约分：$36÷9 = 4$，$4÷4 = 1$，$8÷4 = 2$
则$\frac{1×4×5}{1×2}=10$
4. 计算$\frac{10}{51}×\frac{6}{7}×\frac{34}{25}$：
解：
$\frac{10}{51}×\frac{6}{7}×\frac{34}{25}=\frac{10×6×34}{51×7×25}$
约分：$10÷5 = 2$，$51÷17 = 3$，$34÷17 = 2$，$25÷5 = 5$
则$\frac{2×6×2}{3×7×5}=\frac{24}{105}=\frac{8}{35}$
5. 计算$\frac{3}{10}×\frac{5}{6}×\frac{3}{5}$：
解：
$\frac{3}{10}×\frac{5}{6}×\frac{3}{5}=\frac{3×5×3}{10×6×5}$
约分：$5÷5 = 1$，$10÷5 = 2$，$3÷3 = 1$，$6÷3 = 2$
则$\frac{1×1×3}{2×2×1}=\frac{3}{4}$
6. 计算$\frac{9}{10}×\frac{4}{5}×3$：
解：
$\frac{9}{10}×\frac{4}{5}×3=\frac{9×4×3}{10×5}$
计算：$9×4×3 = 108$，$10×5 = 50$
则$\frac{108}{50}=\frac{54}{25}$
综上，答案依次为$\frac{1}{12}$；$1$；$10$；$\frac{8}{35}$；$\frac{3}{4}$；$\frac{54}{25}$。
