计算:
(1)$(-85)×(-25)×(-4)$; (2)$(-8)×(-\frac {4}{3})×(-1.25)×\frac {5}{4}$;
(3)$(-125)×(-25)×4×0×(-8)$; (4)$(\frac {7}{9}-\frac {5}{6}+\frac {3}{4}-\frac {7}{18})×36$;
(5)$(\frac {1}{6}-\frac {3}{4}+\frac {1}{12})×(-48)$; (6)$(-5)×(-7)+5×(-6)$;
(7)$4×(-3\frac {6}{7})-3×(-3\frac {6}{7})-6×3\frac {6}{7}$; (8)$99\frac {24}{25}×(-25)$;
(9)$(-1\frac {5}{17})×(-3\frac {1}{8})×(+\frac {8}{15})×(+3\frac {7}{9})$;
(10)$(1+\frac {1}{2})×(1+\frac {1}{4})×(1+\frac {1}{6})×... ×(1+\frac {1}{20})×(1-\frac {1}{3})×(1-\frac {1}{5})×(1-\frac {1}{7})×... ×(1-\frac {1}{21})$。
答案:(1)-8500 (2)$-\frac{50}{3}$ (3)0 (4)11 (5)24 (6)5 (7)-27 (8)-2499 (9)$\frac{220}{27}$ (10)1
解析:
(1)解:原式$=(-85)×[(-25)×(-4)]$
$=(-85)×100$
$=-8500$
(2)解:原式$=[(-8)×(-1.25)]×\left(-\frac{4}{3}×\frac{5}{4}\right)$
$=10×\left(-\frac{5}{3}\right)$
$=-\frac{50}{3}$
(3)解:原式$=0$
(4)解:原式$=\frac{7}{9}×36-\frac{5}{6}×36+\frac{3}{4}×36-\frac{7}{18}×36$
$=28 - 30 + 27 - 14$
$=11$
(5)解:原式$=\frac{1}{6}×(-48)-\frac{3}{4}×(-48)+\frac{1}{12}×(-48)$
$=-8 + 36 - 4$
$=24$
(6)解:原式$=35 - 30$
$=5$
(7)解:原式$=(-3\frac{6}{7})×(4 - 3 + 6)$
$=(-\frac{27}{7})×7$
$=-27$
(8)解:原式$=\left(100 - \frac{1}{25}\right)×(-25)$
$=100×(-25)-\frac{1}{25}×(-25)$
$=-2500 + 1$
$=-2499$
(9)解:原式$=\left(-\frac{22}{17}\right)×\left(-\frac{25}{8}\right)×\frac{8}{15}×\frac{34}{9}$
$=\frac{22}{17}×\frac{34}{9}×\frac{25}{8}×\frac{8}{15}$
$=\frac{44}{9}×\frac{5}{3}$
$=\frac{220}{27}$
(10)解:原式$=\frac{3}{2}×\frac{5}{4}×\frac{7}{6}×\cdots×\frac{21}{20}×\frac{2}{3}×\frac{4}{5}×\frac{6}{7}×\cdots×\frac{20}{21}$
$=1$