2.8+29.9+299.9+2999.9+29999.9
=3-0.2+30-0.1+300-0.1+3000-0.1+30000-0.1
=33333-0.6
=33332.4是2.9+29.9+299.9+2999.9+29999.92.9+29.9+299.9+2999.9+29999.9 =3-0.1+30-0.1+300-0.1+3000-0.1+30000-0.1=33333-0.5=33332.53-0.1+30-0.1+300-0.1+3000-0.1+30000-0.1到33333-0.5中间的