题目

数学有理数的乘法与除法,
① [(4*8)*25-8]*125
② 15*(-3/5+1/3)-24*(5/12-7/15)
③ (-47.65)*28/11+(-37.15)*(-28/11)+10.5*(-82/11)
要用简便运算,第一题要有过程.

提问时间：2020-11-04

答案

① [(4*8)*25-8]*125=(4*25-1)*8*125=99*1000=99000
② 15*(-3/5+1/3)-24*(5/12-7/15)
=(-9+5)-(10-56/5)
=-4+6/5
=-14/5
③ (-47.65)*28/11+(-37.15)*(-28/11)+10.5*(-82/11)
=(-47.65+37.15)*28/11+10.5*(-82/11)
=(-10.5)*28/11+10.5*(-82/11)
=-10.5*(28/11+82/11)
=-10.5*10
=-105