观察前三道给出的结果，找规律，直接写出后边两道题的结果。

0.8+0.88=1.68

0.8+0.88+0.888=2.568

0.8+0.88+0.888+0.8888=3.4568

0.8+0.88+0.888+0.8888+0.88888=

0.8+0.88+0.888+0.8888+0.88888+0.888888=