9.7+99.7+999.7+9999.7+99999.7

问题描述:

9.7+99.7+999.7+9999.7+99999.7
简算

9.7+99.7+999.7+9999.7+99999.7=(10-0.3)+(100-0.3)+(1000-0.3)+(10000-0.3)+(100000-0.3)=(10+100+1000+10000+100000)-(0.3+0.3+0.3+0.3+0.3)=111110-1.5=111108.5