99.9+O.2+0.9+9.9+0.2+999.9
18个回答

99.9+0.2+0.9+9.9+0.2+999.9

=(99.9+0.1)+(0.1+0.9)+(9.9+0.1)+(0.1+999.9)

=100+1+10+1000

=1111