9991+999.1+99.91+9.991=99.91x100+99.91x10+99.91+99.91x0.1=99.91x(100+10+1+0.1)=99.91x111.1=11100.001
9991+9.991+999.1+0.91+99=10000.991+1000.01+99=11001.001+99=11100.001
