0.1+0.2+0.3+……+0.9+0.10+0.11+0.12+0.13+……+0.99
=(0.1+0.9)+(0.2+0.8)+......+(0.4+0.6)+0.1+0.5+(0.11+0.99)+(0.12+0.98)+......+(0.54+0.56)+0.55
=1*4+0.6+44*1.1+0.55
=4+1.15+48.4
=53.55
求采纳
相当于(1+2+3+……+9)÷10+(10+12+13+……+99)÷100
=4.5+49.05=53.55
=(0.1+0.9)*9/2+(0.1+0.99)*90/2
=4.5+49.05
=53.55