计算：
(1)$-2.5÷ \frac {5}{8}× (-\frac {1}{4})$； (2)$25÷ (-5)× \frac {1}{5}÷ (-\frac {3}{4})$；
(3)$12× (-\frac {4}{3})÷ 5$； (4)$-2\frac {1}{5}× 2\frac {3}{11}÷ (-2\frac {1}{2})$；
(5)$(-2.1)÷ \frac {7}{10}× (-\frac {10}{7})$； (6)$-8÷ (-4)× \frac {4}{15}$；
(7)$(-3)× 6÷ (-2)× \frac {1}{2}$； (8)$(-\frac {4}{7})÷ (-\frac {3}{14})× (-\frac {7}{3})$；
(9)$(-3)÷ (1\frac {3}{4})× 0.75× |-2\frac {1}{3}|÷ 9$；
(10)$2\frac {1}{5}× |\frac {1}{3}-\frac {1}{2}|× \frac {3}{11}÷ (-1\frac {1}{4})$.
(1)$-2.5÷ \frac {5}{8}× (-\frac {1}{4})$； (2)$25÷ (-5)× \frac {1}{5}÷ (-\frac {3}{4})$；
(3)$12× (-\frac {4}{3})÷ 5$； (4)$-2\frac {1}{5}× 2\frac {3}{11}÷ (-2\frac {1}{2})$；
(5)$(-2.1)÷ \frac {7}{10}× (-\frac {10}{7})$； (6)$-8÷ (-4)× \frac {4}{15}$；
(7)$(-3)× 6÷ (-2)× \frac {1}{2}$； (8)$(-\frac {4}{7})÷ (-\frac {3}{14})× (-\frac {7}{3})$；
(9)$(-3)÷ (1\frac {3}{4})× 0.75× |-2\frac {1}{3}|÷ 9$；
(10)$2\frac {1}{5}× |\frac {1}{3}-\frac {1}{2}|× \frac {3}{11}÷ (-1\frac {1}{4})$.
答案：(1)1 (2)$\frac{4}{3}$ (3)$-\frac{16}{5}$ (4)2 (5)$\frac{30}{7}$ (6)$\frac{8}{15}$ (7)$\frac{9}{2}$ (8)$-\frac{56}{9}$ (9)$-\frac{1}{3}$ (10)$-\frac{2}{25}$
解析：
(1)$-2.5÷\frac{5}{8}×\left(-\frac{1}{4}\right)$
$=\frac{5}{2}×\frac{8}{5}×\frac{1}{4}$
$=4×\frac{1}{4}$
$=1$
(2)$25÷(-5)×\frac{1}{5}÷\left(-\frac{3}{4}\right)$
$=25×\frac{1}{5}×\frac{1}{5}×\frac{4}{3}$
$=1×\frac{4}{3}$
$=\frac{4}{3}$
(3)$12×\left(-\frac{4}{3}\right)÷5$
$=-16×\frac{1}{5}$
$=-\frac{16}{5}$
(4)$-2\frac{1}{5}×2\frac{3}{11}÷\left(-2\frac{1}{2}\right)$
$=\frac{11}{5}×\frac{25}{11}×\frac{2}{5}$
$=5×\frac{2}{5}$
$=2$
(5)$(-2.1)÷\frac{7}{10}×\left(-\frac{10}{7}\right)$
$=\frac{21}{10}×\frac{10}{7}×\frac{10}{7}$
$=3×\frac{10}{7}$
$=\frac{30}{7}$
(6)$-8÷(-4)×\frac{4}{15}$
$=2×\frac{4}{15}$
$=\frac{8}{15}$
(7)$(-3)×6÷(-2)×\frac{1}{2}$
$=3×6×\frac{1}{2}×\frac{1}{2}$
$=18×\frac{1}{4}$
$=\frac{9}{2}$
(8)$\left(-\frac{4}{7}\right)÷\left(-\frac{3}{14}\right)×\left(-\frac{7}{3}\right)$
$=-\frac{4}{7}×\frac{14}{3}×\frac{7}{3}$
$=-\frac{8}{3}×\frac{7}{3}$
$=-\frac{56}{9}$
(9)$(-3)÷\left(1\frac{3}{4}\right)×0.75×\left|-2\frac{1}{3}\right|÷9$
$=-3×\frac{4}{7}×\frac{3}{4}×\frac{7}{3}×\frac{1}{9}$
$=-3×\frac{1}{9}$
$=-\frac{1}{3}$
(10)$2\frac{1}{5}×\left|\frac{1}{3}-\frac{1}{2}\right|×\frac{3}{11}÷\left(-1\frac{1}{4}\right)$
$=-\frac{11}{5}×\frac{1}{6}×\frac{3}{11}×\frac{4}{5}$
$=-\frac{1}{10}×\frac{4}{5}$
$=-\frac{2}{25}$
$=\frac{5}{2}×\frac{8}{5}×\frac{1}{4}$
$=4×\frac{1}{4}$
$=1$
(2)$25÷(-5)×\frac{1}{5}÷\left(-\frac{3}{4}\right)$
$=25×\frac{1}{5}×\frac{1}{5}×\frac{4}{3}$
$=1×\frac{4}{3}$
$=\frac{4}{3}$
(3)$12×\left(-\frac{4}{3}\right)÷5$
$=-16×\frac{1}{5}$
$=-\frac{16}{5}$
(4)$-2\frac{1}{5}×2\frac{3}{11}÷\left(-2\frac{1}{2}\right)$
$=\frac{11}{5}×\frac{25}{11}×\frac{2}{5}$
$=5×\frac{2}{5}$
$=2$
(5)$(-2.1)÷\frac{7}{10}×\left(-\frac{10}{7}\right)$
$=\frac{21}{10}×\frac{10}{7}×\frac{10}{7}$
$=3×\frac{10}{7}$
$=\frac{30}{7}$
(6)$-8÷(-4)×\frac{4}{15}$
$=2×\frac{4}{15}$
$=\frac{8}{15}$
(7)$(-3)×6÷(-2)×\frac{1}{2}$
$=3×6×\frac{1}{2}×\frac{1}{2}$
$=18×\frac{1}{4}$
$=\frac{9}{2}$
(8)$\left(-\frac{4}{7}\right)÷\left(-\frac{3}{14}\right)×\left(-\frac{7}{3}\right)$
$=-\frac{4}{7}×\frac{14}{3}×\frac{7}{3}$
$=-\frac{8}{3}×\frac{7}{3}$
$=-\frac{56}{9}$
(9)$(-3)÷\left(1\frac{3}{4}\right)×0.75×\left|-2\frac{1}{3}\right|÷9$
$=-3×\frac{4}{7}×\frac{3}{4}×\frac{7}{3}×\frac{1}{9}$
$=-3×\frac{1}{9}$
$=-\frac{1}{3}$
(10)$2\frac{1}{5}×\left|\frac{1}{3}-\frac{1}{2}\right|×\frac{3}{11}÷\left(-1\frac{1}{4}\right)$
$=-\frac{11}{5}×\frac{1}{6}×\frac{3}{11}×\frac{4}{5}$
$=-\frac{1}{10}×\frac{4}{5}$
$=-\frac{2}{25}$