《2025年通城学典课时作业本七年级数学上册人教版南通专版》

1. 计算:
(1)$(-8)×11×(-12.5)×(-\frac {1}{11})$;
(2)$(-20)×(-\frac {2}{7})×5×(-\frac {7}{8})$;
(3)$(-4\frac {1}{2})÷\frac {7}{25}×(-\frac {4}{3})×(-1\frac {2}{5})$.

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)$60×(-\frac {3}{4}-\frac {5}{12}+\frac {5}{6}-1)$.

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)$[1\frac {2}{13}-(\frac {5}{8}-\frac {1}{6}+\frac {7}{12})×24]÷(-5)$.

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$=[1\frac {2}{13}-(15-4+14)]÷(-5)=(\frac {15}{13}-25)×(-\frac {1}{5})=\frac {15}{13}×(-\frac {1}{5})-25×(-\frac {1}{5})=-\frac {3}{13}+5=4\frac {10}{13}$

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)$2\frac {1}{3}×\frac {7}{13}-(-\frac {7}{13})×(-14)+(-\frac {4}{3})÷\frac {13}{7}$.

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$=2\frac {1}{3}×\frac {7}{13}-\frac {7}{13}×14-\frac {4}{3}×\frac {7}{13}=\frac {7}{13}×(2\frac {1}{3}-14-\frac {4}{3})=\frac {7}{13}×(-13)=-7$