计算98+998+9998+``````+999999``````(50个9)8=

问题描述:

计算98+998+9998+``````+999999``````(50个9)8=

98+998+9998+``````+999999``````(50个9)8
=100-2+1000-2+10000-2+.+1000000.00000-2(50个0)
=1111.111100(48个1)-2*50
=111.111000(47个1)