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1. $(-\frac {3}{8})×(-\frac {56}{3})= $
答案
7
解析
$(-\frac{3}{8})×(-\frac{56}{3})$
$=\frac{3}{8}×\frac{56}{3}$
$=\frac{56}{8}$
$=7$
$=\frac{3}{8}×\frac{56}{3}$
$=\frac{56}{8}$
$=7$
2. $21\frac {7}{8}÷(-7)= $
答案
$-3\frac{1}{8}$
解析
$21\frac{7}{8}÷(-7)$
$=\left(21+\frac{7}{8}\right)×\left(-\frac{1}{7}\right)$
$=21×\left(-\frac{1}{7}\right)+\frac{7}{8}×\left(-\frac{1}{7}\right)$
$=-3-\frac{1}{8}$
$=-3\frac{1}{8}$
$=\left(21+\frac{7}{8}\right)×\left(-\frac{1}{7}\right)$
$=21×\left(-\frac{1}{7}\right)+\frac{7}{8}×\left(-\frac{1}{7}\right)$
$=-3-\frac{1}{8}$
$=-3\frac{1}{8}$
3. $(-5)÷(-\frac {5}{7})×1\frac {2}{7}= $
答案
9
解析
$(-5)÷(-\frac{5}{7})×1\frac{2}{7}$
$=(-5)×(-\frac{7}{5})×\frac{9}{7}$
$=7×\frac{9}{7}$
$=9$
$=(-5)×(-\frac{7}{5})×\frac{9}{7}$
$=7×\frac{9}{7}$
$=9$
4. $-32÷2×\frac {1}{8}= $
答案
-2
解析
$-32÷2×\frac{1}{8}=-16×\frac{1}{8}=-2$
5. $(-8)×(-218)×(-0.125)= $
答案
-218
解析
$(-8) × (-218) × (-0.125)$
$=(-8) × (-0.125) × (-218)$
$=1 × (-218)$
$=-218$
$=(-8) × (-0.125) × (-218)$
$=1 × (-218)$
$=-218$
6. $(-135)×(-\frac {4}{9})÷(+2\frac {1}{7})= $
答案
28
解析
$(-135)×(-\frac{4}{9})÷(+2\frac{1}{7})$
$=(-135)×(-\frac{4}{9})÷\frac{15}{7}$
$=(-135)×(-\frac{4}{9})×\frac{7}{15}$
$=135×\frac{4}{9}×\frac{7}{15}$
$=15×4×\frac{7}{15}$
$=4×7$
$=28$
$=(-135)×(-\frac{4}{9})÷\frac{15}{7}$
$=(-135)×(-\frac{4}{9})×\frac{7}{15}$
$=135×\frac{4}{9}×\frac{7}{15}$
$=15×4×\frac{7}{15}$
$=4×7$
$=28$
7. $(-75)÷(-5)×\frac {1}{5}$
答案
3
解析
$(-75)÷(-5)×\frac{1}{5}$
$=15×\frac{1}{5}$
$=3$
$=15×\frac{1}{5}$
$=3$
8. $2\frac {5}{24}×(-\frac {8}{9})×0$
答案
0
解析
$2\frac{5}{24} × \left(-\frac{8}{9}\right) × 0 = 0$
9. $-|\frac {2}{7}|×(-28)×(-0.25)$
答案
-2
解析
$-|\frac{2}{7}| × (-28) × (-0.25)$
$=-\frac{2}{7} × (-28) × (-\frac{1}{4})$
$=8 × (-\frac{1}{4})$
$=-2$
$=-\frac{2}{7} × (-28) × (-\frac{1}{4})$
$=8 × (-\frac{1}{4})$
$=-2$
10. $(\frac {1}{3}-\frac {3}{4}+\frac {1}{6}-\frac {1}{9})×(-36)$
答案
13
解析
$(\frac{1}{3} - \frac{3}{4} + \frac{1}{6} - \frac{1}{9}) × (-36)$
$=\frac{1}{3} × (-36) - \frac{3}{4} × (-36) + \frac{1}{6} × (-36) - \frac{1}{9} × (-36)$
$=-12 + 27 - 6 + 4$
$=13$
$=\frac{1}{3} × (-36) - \frac{3}{4} × (-36) + \frac{1}{6} × (-36) - \frac{1}{9} × (-36)$
$=-12 + 27 - 6 + 4$
$=13$
11. $(-2\frac {1}{2})×(-\frac {1}{3})×\frac {3}{10}×(-1\frac {1}{3})$
答案
$-\frac{1}{3}$
解析
$(-2\frac{1}{2})×(-\frac{1}{3})×\frac{3}{10}×(-1\frac{1}{3})$
$=(-\frac{5}{2})×(-\frac{1}{3})×\frac{3}{10}×(-\frac{4}{3})$
$=-\left(\frac{5}{2}×\frac{1}{3}×\frac{3}{10}×\frac{4}{3}\right)$
$=-\left(\frac{5×1×3×4}{2×3×10×3}\right)$
$=-\left(\frac{60}{180}\right)$
$=-\frac{1}{3}$
$=(-\frac{5}{2})×(-\frac{1}{3})×\frac{3}{10}×(-\frac{4}{3})$
$=-\left(\frac{5}{2}×\frac{1}{3}×\frac{3}{10}×\frac{4}{3}\right)$
$=-\left(\frac{5×1×3×4}{2×3×10×3}\right)$
$=-\left(\frac{60}{180}\right)$
$=-\frac{1}{3}$
12. $(-\frac {7}{8})÷(1\frac {3}{4}-\frac {7}{8}-\frac {7}{12})$
答案
-3
解析
$(-\frac{7}{8})÷(1\frac{3}{4}-\frac{7}{8}-\frac{7}{12})$
$=(-\frac{7}{8})÷(\frac{7}{4}-\frac{7}{8}-\frac{7}{12})$
$=(-\frac{7}{8})÷(\frac{42}{24}-\frac{21}{24}-\frac{14}{24})$
$=(-\frac{7}{8})÷\frac{7}{24}$
$=(-\frac{7}{8})×\frac{24}{7}$
$=-3$
$=(-\frac{7}{8})÷(\frac{7}{4}-\frac{7}{8}-\frac{7}{12})$
$=(-\frac{7}{8})÷(\frac{42}{24}-\frac{21}{24}-\frac{14}{24})$
$=(-\frac{7}{8})÷\frac{7}{24}$
$=(-\frac{7}{8})×\frac{24}{7}$
$=-3$
13. $-13×\frac {2}{3}-0.34÷\frac {7}{2}+\frac {1}{3}×(-13)-\frac {5}{7}×0.34$
答案
-13.34
解析
$-13×\frac{2}{3}-0.34÷\frac{7}{2}+\frac{1}{3}×(-13)-\frac{5}{7}×0.34$
$=-13×\left(\frac{2}{3}+\frac{1}{3}\right)-0.34×\left(\frac{2}{7}+\frac{5}{7}\right)$
$=-13×1 - 0.34×1$
$=-13 - 0.34$
$=-13.34$
$=-13×\left(\frac{2}{3}+\frac{1}{3}\right)-0.34×\left(\frac{2}{7}+\frac{5}{7}\right)$
$=-13×1 - 0.34×1$
$=-13 - 0.34$
$=-13.34$
