1. 计算:
(1)$(-8)×11×(-12.5)×(-\frac {1}{11})$;
(2)$(-20)×(-\frac {2}{7})×5×(-\frac {7}{8})$;
(3)$(-4\frac {1}{2})÷\frac {7}{25}×(-\frac {4}{3})×(-1\frac {2}{5})$.
(1)$(-8)×11×(-12.5)×(-\frac {1}{11})$;
(2)$(-20)×(-\frac {2}{7})×5×(-\frac {7}{8})$;
(3)$(-4\frac {1}{2})÷\frac {7}{25}×(-\frac {4}{3})×(-1\frac {2}{5})$.
答案:1. (1)原式$=-8×12.5×11×\frac {1}{11}=-100$ (2)原式$=-20×5×\frac {2}{7}×\frac {7}{8}=-25$ (3)原式$=-\frac {9}{2}×(-\frac {4}{3})×\frac {25}{7}×(-\frac {7}{5})=-30$
2. 计算:
(1)$(-\frac {1}{12}-\frac {1}{36}+\frac {1}{6})×(-36)$;
(2)$60×(-\frac {3}{4}-\frac {5}{12}+\frac {5}{6}-1)$.
(1)$(-\frac {1}{12}-\frac {1}{36}+\frac {1}{6})×(-36)$;
(2)$60×(-\frac {3}{4}-\frac {5}{12}+\frac {5}{6}-1)$.
答案:2. (1)原式$=(-\frac {1}{12})×(-36)-\frac {1}{36}×(-36)+\frac {1}{6}×(-36)=3+1-6=-2$ (2)原式$=60×(-\frac {3}{4})+60×(-\frac {5}{12})+60×\frac {5}{6}+60×(-1)=-45-25+50-60=-80$
3. 计算:
(1)$(-99\frac {11}{12})×24$;
(2)$(-49\frac {7}{16})÷(-7)$;
(3)$(-32\frac {16}{25})÷(-8×4)$;
(4)$[1\frac {2}{13}-(\frac {5}{8}-\frac {1}{6}+\frac {7}{12})×24]÷(-5)$.
(1)$(-99\frac {11}{12})×24$;
(2)$(-49\frac {7}{16})÷(-7)$;
(3)$(-32\frac {16}{25})÷(-8×4)$;
(4)$[1\frac {2}{13}-(\frac {5}{8}-\frac {1}{6}+\frac {7}{12})×24]÷(-5)$.
答案:3. (1)原式$=(-100+\frac {1}{12})×24=-100×24+\frac {1}{12}×24=-2400+2=-2398$ (2)原式$=(-49-\frac {7}{16})×(-\frac {1}{7})=7+\frac {1}{16}=7\frac {1}{16}$ (3)原式$=(-32\frac {16}{25})÷(-32)=(32+\frac {16}{25})×\frac {1}{32}=32×\frac {1}{32}+\frac {16}{25}×\frac {1}{32}=1\frac {1}{50}$ (4)原式$=[1\frac {2}{13}-(15-4+14)]÷(-5)=(\frac {15}{13}-25)×(-\frac {1}{5})=\frac {15}{13}×(-\frac {1}{5})-25×(-\frac {1}{5})=-\frac {3}{13}+5=4\frac {10}{13}$
解析:
(1)解:原式$=(-100+\frac{1}{12})×24$
$=-100×24+\frac{1}{12}×24$
$=-2400 + 2$
$=-2398$
(2)解:原式$=(-49-\frac{7}{16})×(-\frac{1}{7})$
$=-49×(-\frac{1}{7})+(-\frac{7}{16})×(-\frac{1}{7})$
$=7+\frac{1}{16}$
$=7\frac{1}{16}$
(3)解:原式$=(-32\frac{16}{25})÷(-32)$
$=(32+\frac{16}{25})×\frac{1}{32}$
$=32×\frac{1}{32}+\frac{16}{25}×\frac{1}{32}$
$=1+\frac{1}{50}$
$=1\frac{1}{50}$
(4)解:原式$=[1\frac{2}{13}-(\frac{5}{8}×24-\frac{1}{6}×24+\frac{7}{12}×24)]÷(-5)$
$=[\frac{15}{13}-(15 - 4 + 14)]÷(-5)$
$=(\frac{15}{13}-25)×(-\frac{1}{5})$
$=\frac{15}{13}×(-\frac{1}{5})-25×(-\frac{1}{5})$
$=-\frac{3}{13}+5$
$=4\frac{10}{13}$
$=-100×24+\frac{1}{12}×24$
$=-2400 + 2$
$=-2398$
(2)解:原式$=(-49-\frac{7}{16})×(-\frac{1}{7})$
$=-49×(-\frac{1}{7})+(-\frac{7}{16})×(-\frac{1}{7})$
$=7+\frac{1}{16}$
$=7\frac{1}{16}$
(3)解:原式$=(-32\frac{16}{25})÷(-32)$
$=(32+\frac{16}{25})×\frac{1}{32}$
$=32×\frac{1}{32}+\frac{16}{25}×\frac{1}{32}$
$=1+\frac{1}{50}$
$=1\frac{1}{50}$
(4)解:原式$=[1\frac{2}{13}-(\frac{5}{8}×24-\frac{1}{6}×24+\frac{7}{12}×24)]÷(-5)$
$=[\frac{15}{13}-(15 - 4 + 14)]÷(-5)$
$=(\frac{15}{13}-25)×(-\frac{1}{5})$
$=\frac{15}{13}×(-\frac{1}{5})-25×(-\frac{1}{5})$
$=-\frac{3}{13}+5$
$=4\frac{10}{13}$
4. 计算:
(1)$25×\frac {3}{4}-(-25)×\frac {1}{2}+25×(-\frac {1}{4})$;
(2)$(-3)×(-\frac {1}{4})+0.25×24.5+(-3\frac {1}{2})×25\%$;
(3)$-14×\frac {2}{3}-0.35×\frac {2}{7}+\frac {1}{3}×(-14)-\frac {5}{7}×0.35$;
(4)$2\frac {1}{3}×\frac {7}{13}-(-\frac {7}{13})×(-14)+(-\frac {4}{3})÷\frac {13}{7}$.
(1)$25×\frac {3}{4}-(-25)×\frac {1}{2}+25×(-\frac {1}{4})$;
(2)$(-3)×(-\frac {1}{4})+0.25×24.5+(-3\frac {1}{2})×25\%$;
(3)$-14×\frac {2}{3}-0.35×\frac {2}{7}+\frac {1}{3}×(-14)-\frac {5}{7}×0.35$;
(4)$2\frac {1}{3}×\frac {7}{13}-(-\frac {7}{13})×(-14)+(-\frac {4}{3})÷\frac {13}{7}$.
答案:4. (1)原式$=25×(\frac {3}{4}+\frac {1}{2}-\frac {1}{4})=25×1=25$ (2)原式$=\frac {1}{4}×(3+24.5-3\frac {1}{2})=\frac {1}{4}×24=6$ (3)原式$=-14×(\frac {2}{3}+\frac {1}{3})-0.35×(\frac {2}{7}+\frac {5}{7})=-14-0.35=-14.35$ (4)原式$=2\frac {1}{3}×\frac {7}{13}-\frac {7}{13}×14-\frac {4}{3}×\frac {7}{13}=\frac {7}{13}×(2\frac {1}{3}-14-\frac {4}{3})=\frac {7}{13}×(-13)=-7$
解析:
(1)解:原式$=25×\frac {3}{4}+25×\frac {1}{2}+25×(-\frac {1}{4})$
$=25×(\frac {3}{4}+\frac {1}{2}-\frac {1}{4})$
$=25×1$
$=25$
(2)解:原式$=(-3)×(-\frac {1}{4})+\frac {1}{4}×24.5+(-3.5)×\frac {1}{4}$
$=\frac {1}{4}×(3+24.5-3.5)$
$=\frac {1}{4}×24$
$=6$
(3)解:原式$=-14×\frac {2}{3}+\frac {1}{3}×(-14)-0.35×\frac {2}{7}-\frac {5}{7}×0.35$
$=-14×(\frac {2}{3}+\frac {1}{3})-0.35×(\frac {2}{7}+\frac {5}{7})$
$=-14×1-0.35×1$
$=-14-0.35$
$=-14.35$
(4)解:原式$=2\frac {1}{3}×\frac {7}{13}-\frac {7}{13}×14-\frac {4}{3}×\frac {7}{13}$
$=\frac {7}{13}×(2\frac {1}{3}-14-\frac {4}{3})$
$=\frac {7}{13}×(2+\frac {1}{3}-\frac {4}{3}-14)$
$=\frac {7}{13}×(-13)$
$=-7$
$=25×(\frac {3}{4}+\frac {1}{2}-\frac {1}{4})$
$=25×1$
$=25$
(2)解:原式$=(-3)×(-\frac {1}{4})+\frac {1}{4}×24.5+(-3.5)×\frac {1}{4}$
$=\frac {1}{4}×(3+24.5-3.5)$
$=\frac {1}{4}×24$
$=6$
(3)解:原式$=-14×\frac {2}{3}+\frac {1}{3}×(-14)-0.35×\frac {2}{7}-\frac {5}{7}×0.35$
$=-14×(\frac {2}{3}+\frac {1}{3})-0.35×(\frac {2}{7}+\frac {5}{7})$
$=-14×1-0.35×1$
$=-14-0.35$
$=-14.35$
(4)解:原式$=2\frac {1}{3}×\frac {7}{13}-\frac {7}{13}×14-\frac {4}{3}×\frac {7}{13}$
$=\frac {7}{13}×(2\frac {1}{3}-14-\frac {4}{3})$
$=\frac {7}{13}×(2+\frac {1}{3}-\frac {4}{3}-14)$
$=\frac {7}{13}×(-13)$
$=-7$