《2025年名校课堂七年级数学上册人教版》

计算：
(1)$(-20)× (-1\frac {1}{5})× (-0.3)× 5$.
(2)$(\frac {5}{6}+\frac {7}{8}-\frac {23}{24})× (-48)$.
(3)$25× \frac {3}{4}-(-25)× \frac {1}{2}+25× (-\frac {1}{4})$.
(4)$(\frac {2}{3}-\frac {3}{4}+\frac {1}{6})÷ (-\frac {1}{24})$.
(5)$36× (-99\frac {71}{72})$.
(6)$[1\frac {2}{13}-(\frac {5}{8}-\frac {1}{6}+\frac {7}{12})× 24]÷ (-5)$.
(7)$(-\frac {1}{30})÷ (\frac {2}{3}-\frac {1}{10}+\frac {1}{6}-\frac {2}{5})$.
(8)$9\frac {11}{12}× (-12)+35.5× 4-5.5× 4$.
(9)$0.7× 1\frac {4}{9}+2\frac {3}{4}× (-17)+0.7× \frac {5}{9}+\frac {1}{4}× (-17)$.

答案：
(1)原式=$[(-20)×(-1\frac{1}{5})]×[(-0.3)×5]=24×(-1.5)=-36$。
(2)原式=$\frac{5}{6}×(-48)+\frac{7}{8}×(-48)-\frac{23}{24}×(-48)=-40 - 42 + 46=-36$。
(3)原式=$25×\frac{3}{4}+25×\frac{1}{2}+25×(-\frac{1}{4})=25×(\frac{3}{4}+\frac{1}{2}-\frac{1}{4})=25×1=25$。
(4)原式=$(\frac{2}{3}-\frac{3}{4}+\frac{1}{6})×(-24)=\frac{2}{3}×(-24)-\frac{3}{4}×(-24)+\frac{1}{6}×(-24)=-16 + 18 - 4=-2$。
(5)原式=$36×[(-100)+\frac{1}{72}]=36×(-100)+36×\frac{1}{72}=-3600+\frac{1}{2}=-3599\frac{1}{2}$。
(6)原式=$[1\frac{2}{13}-(\frac{5}{8}×24 - \frac{1}{6}×24+\frac{7}{12}×24)]÷(-5)=[1\frac{2}{13}-(15 - 4+14)]÷(-5)=(\frac{15}{13}-25)×(-\frac{1}{5})=\frac{15}{13}×(-\frac{1}{5})-25×(-\frac{1}{5})=-\frac{3}{13}+5=4\frac{10}{13}$。
(7)因为$(\frac{2}{3}-\frac{1}{10}+\frac{1}{6}-\frac{2}{5})÷(-\frac{1}{30})=(\frac{2}{3}-\frac{1}{10}+\frac{1}{6}-\frac{2}{5})×(-30)=-20 + 3 - 5 + 12=-10$，所以$(-\frac{1}{30})÷(\frac{2}{3}-\frac{1}{10}+\frac{1}{6}-\frac{2}{5})=-\frac{1}{10}$。
(8)原式=$(10-\frac{1}{12})×(-12)+(35.5 - 5.5)×4=10×(-12)-\frac{1}{12}×(-12)+30×4=-120 + 1+120=1$。
(9)原式=$(0.7×1\frac{4}{9}+0.7×\frac{5}{9})+[2\frac{3}{4}×(-17)+\frac{1}{4}×(-17)]=0.7×(1\frac{4}{9}+\frac{5}{9})+(-17)×(2\frac{3}{4}+\frac{1}{4})=0.7×2+(-17)×3=1.4 - 51=-49.6$。