99.9+99.99+99.999简便计算

问题描述:

99.9+99.99+99.999简便计算

原式=(100-0.1)+(100-0.01)+(100-0.001)=300-0.111=299.889

99.9+99.99+99.999
=100+100+100-0.1-0.01-0.001
=300-0.111
=299+1-0.111
=299+0.889
=299.889

300-0.111=299.889

99.9+99.99+99.999
=100-0.1+100-0.01+100-0.001
=300-0.111
=299.889

原式
=(100-0.1)+(100-0.01)+(100-0.001)
=100×3-0.1-0.01-0.001
=299.889