七年级数学有理数乘法简便计算(1) (-1005/34)×(-68) (2) 99 8/9 ×(-9/10)

问题描述:

七年级数学有理数乘法简便计算
(1) (-1005/34)×(-68) (2) 99 8/9 ×(-9/10)

(1) (-1005/34)×(-68) =[(-1005)*(-68)]/34 =(1005*68)/34 =1005*2 =2010 (2) 99 8/9 ×(-9/10) =[998*(-9)]/(9*10) =-998/10 =-99.8