《2025年一本计算题满分训练七年级数学全一册人教版》

1.用简便算法计算下列各题:
(1)$3\frac {1}{7}×(-\frac {88}{7})×\frac {21}{22}×(-\frac {7}{22})$;
(2)$16.8×\frac {7}{32}+7.6×\frac {7}{16}$;
(3)【易错】$(-3.61)×0.75+0.61×\frac {3}{4}+(-0.2)×75\% $;
(4)$(-13)×\frac {2}{3}-0.34×\frac {2}{7}+\frac {1}{3}×(-13)-\frac {5}{7}×0.34$.

答案： 1.
(1)12
(2)7
(3)$-\frac{12}{5}$
(4)-13.34

2.用简便算法计算下列各题:
(1)$\frac {1}{2}×\frac {2}{3}×\frac {3}{4}×... ×\frac {49}{50}=$$\frac{1}{50}$;
(2)【易错】$(\frac {1}{100}-1)×(\frac {1}{99}-1)×(\frac {1}{98}-1)×... ×(\frac {1}{2}-1)=$$-\frac{1}{100}$;
(3)$(1+\frac {1}{2})×(1+\frac {1}{4})×(1+\frac {1}{6})×... ×(1+\frac {1}{20})×(1-\frac {1}{3})×(1-\frac {1}{5})×(1-\frac {1}{7})×... ×(1-\frac {1}{21})=$1.

答案： 2.
(1)$\frac{1}{50}$
(2)$-\frac{1}{100}$
(3)1