1991*0.5+1992*2.5+1993/12.5(用简便方法计算,并附带过程)

问题描述:

1991*0.5+1992*2.5+1993/12.5(用简便方法计算,并附带过程)
1991*0.5+1992*2.5+1993/12.5(用简便方法计算,并附带过程)

=(2000-9)x0.5+(2000-8)*2.5+(2000-7)/12.5
=2000x0.5-4.5+2000*2.5-20+2000/12.5-7/12.5
=1000+5000+800-4.5-20-0.56
=6774.94