《2025年名校课堂七年级数学上册人教版陕西专版》

计算：
(1)$(-10)×(-7.32)×(-0.1)$.
(2)$(-20)×(-1\frac {1}{5})×(-0.3)×5$.
(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)$[\frac {15}{13}-(\frac {5}{8}-\frac {1}{6}+\frac {7}{12})×24]÷(-5)$.
(7)$(-\frac {1}{30})÷(\frac {2}{3}-\frac {1}{10}+\frac {1}{6}-\frac {2}{5})$.
(8)$0.7×1\frac {4}{9}+2\frac {3}{4}×(-17)+0.7×\frac {5}{9}+\frac {1}{4}×(-17)$.

答案： 针对训练
解：
(1)原式=$-(10×0.1)×7.32=-7.32$。
(2)原式=$-(20×0.3)×(\frac{6}{5}×5)=-6×6=-36$。
(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=$[\frac{15}{13}-\frac{5}{8}×24-\frac{1}{6}×24+\frac{7}{12}×24]÷(-5)=[\frac{15}{13}-(15 - 4 + 14)]÷(-5)=(\frac{15}{13}-25)×(-\frac{1}{5})=\frac{15}{13}×(-\frac{1}{5})-25×(-\frac{1}{5})=-\frac{3}{13}+5=4\frac{10}{13}$。
(7)原式的倒数为$(\frac{2}{3}-\frac{1}{10}+\frac{1}{6}-\frac{2}{5})÷(-\frac{1}{30})=(\frac{2}{3}-\frac{1}{10}+\frac{1}{6}-\frac{2}{5})×(-30)=\frac{2}{3}×(-30)-\frac{1}{10}×(-30)+\frac{1}{6}×(-30)-\frac{2}{5}×(-30)=-20 + 3 - 5 + 12=-10$.故原式=$-\frac{1}{10}$。
(8)原式=$(0.7×1\frac{4}{9}+0.7×\frac{5}{9})+[2\frac{3}{4}×(-17)+\frac{1}{4}×(-17)]=0.7×(1\frac{4}{9}+\frac{5}{9})+(-17)×(2\frac{3}{4}+\frac{1}{4})=0.7×2+(-17)×3=1.4 - 51=-49.6$.