More answers:

NO 1.
(1/9)*9=1
1/9=0.111111....
0.111111....*9=0.999999....=(1/9)*9=1

No.2

(2/3)+(1/3)=1
0.666666...+0.333333...=0.999999....=1

No.3

(1/3)*3=1
0.333333....*3=0.999999....=1

所有跟帖： 

• ^_^ -烛龙- ♂ (0 bytes) () 04/08/2009 postreply 13:52:11

• 笑笑笑，不帮我敲打那个大笨蛋，不够哥门 :P -云是天上的花- ♀ (0 bytes) () 04/08/2009 postreply 15:37:00

• nice. 安娜有颗可爱的童心 :D -云是天上的花- ♀ (0 bytes) () 04/08/2009 postreply 15:35:15

• 呵呵:) -房客- ♂ (0 bytes) () 04/08/2009 postreply 15:39:27

• ^^ -云是天上的花- ♀ (0 bytes) () 04/08/2009 postreply 16:30:01