简便运算 0.9+1.99+2.99+3.9999
问题描述：
简便运算 0.9+1.99+2.99+3.9999
答
0.9+1.99+2.99+3.9999
=1-0.1+2-0.01+3-0.01+4-0.0001
=10-0.1201
=9.8799
答
0.9+1.99+2.99+3.9999
=1+2+3+4-(0.1+0.01+0.001+0.0001)
=10-0.1111
=9.8889