《2025年一本计算题满分训练七年级数学全一册人教版》

1. 计算:
(1)$(\frac {2}{3}+\frac {1}{4})×12$;
(2)【易错】$(-24)×(1-\frac {3}{4}+\frac {1}{6}-\frac {5}{8})$;
(3)$(-20)×(\frac {1}{2}-\frac {3}{10}+\frac {2}{5}-\frac {1}{4})$;
(4)$(-\frac {1}{3}-\frac {1}{4}+\frac {1}{5}-\frac {7}{15})×(-60)$.

答案： 1.
(1)11
(2)5
(3)-7
(4)51
解:
(1)原式$=\frac{2}{3}×12+\frac{1}{4}×12=8+3=11.$
(2)原式$=(-24)×1-(-24)×\frac{3}{4}+(-24)×\frac{1}{6}-(-24)×\frac{5}{8}=(-24)-(-18)+(-4)-(-15)=(-24)+18-4+15=5.$
(3)原式$=(-20)×\frac{1}{2}+20×\frac{3}{10}-20×\frac{2}{5}+20×\frac{1}{4}=-10+6-8+5=-7.$
(4)原式$=(-\frac{1}{3})×(-60)-\frac{1}{4}×(-60)+\frac{1}{5}×(-60)-\frac{7}{15}×(-60)=20-(-15)+(-12)-(-28)=20+15-12+28=51.$

2. 用简便方法计算:
(1)$(-9)×(-48)+(-9)×(-32)$;
(2)$(-7.3)×42.07+(-2.07)×(-7.3)$;
(3)$(-7)×(-\frac {22}{7})+19×(-\frac {22}{7})-5×(-\frac {22}{7})$;
(4)$\frac {5}{17}×(-\frac {3}{7})+\frac {5}{17}×(-\frac {4}{7})-\frac {5}{17}×1\frac {3}{7}$.

答案： 2.
(1)720
(2)-292
(3)-22
(4)$-\frac{5}{7}$
解:
(1)原式$=(-9)×[(-48)+(-32)]=(-9)×(-80)=720.$
(2)原式$=(-7.3)×(42.07-2.07)=(-7.3)×40=-292.$
(3)原式$=(-7+19-5)×(-\frac{22}{7})=7×(-\frac{22}{7})=-22.$
(4)原式$=\frac{5}{17}×(-\frac{3}{7})+\frac{5}{17}×(-\frac{4}{7})-\frac{5}{17}×\frac{10}{7}=\frac{5}{17}×(-\frac{3}{7}-\frac{4}{7}-\frac{10}{7})=\frac{5}{17}×(-\frac{17}{7})=-\frac{5}{7}.$

3. 用简便方法计算:
(1)$(-20\frac {1}{5})×50$;
(2)$99\frac {17}{18}×(-18)$.

答案： 3.
(1)-1 010
(2)-1 799
方法:拆分法
解:
(1)原式$=(-20-\frac{1}{5})×50=(-20)×50-\frac{1}{5}×50=-1000-10=-1010.$
(2)原式$=(100-\frac{1}{18})×(-18)=100×(-18)-\frac{1}{18}×(-18)=-1800+1=-1799.$