4. 用计算器计算每组中的前三题,再直接写出最后一题的得数。
(1) $0.1+0.11=$
$0.1+0.11+0.111=$
$0.1+0.11+0.111+0.1111=$
……
$0.1+0.11+0.111+0.1111+\dots +\underset{9个1}{\underbrace{0.11··· 1}}=$
(2) $0.8+0.88=$
$0.8+0.88+0.888=$
$0.8+0.88+0.888+0.8888=$
……
$0.8+0.88+\dots +\underset{6个8}{\underbrace{0.88··· 8}}=$

(1)
$0.1+0.11=0.21$
$0.1+0.11+0.111=0.321$
$0.1+0.11+0.111+0.1111=0.4321$
$0.1+0.11+0.111+0.1111+\dots +\underset{9个1}{\underbrace{0.11··· 1}}=0.987654321$
(2)
$0.8+0.88=1.68$
$0.8+0.88+0.888=2.568$
$0.8+0.88+0.888+0.8888=3.4568$
$0.8+0.88+\dots +\underset{6个8}{\underbrace{0.88··· 8}}=5.234568$

5.

(1) 哪辆小汽车的车身高? 高多少米?
(2) 哪辆小汽车的车身长? 长多少米?

(1)
$1.54 ＞ 1.46$
$1.54 - 1.46 = 0.08$（米）
答：左边的小汽车车身高，高0.08米。
(2)
$5.27 ＞ 4.18$
$5.27 - 4.18 = 1.09$（米）
答：左边的小汽车车身长，长1.09米。