conversation-repost

There are 4 mathematicians - AA, BB, CC and DD - having lunch in a hotel.
Suddenly, AA thinks of 2 integer numbers greater than 1 and says,
"The sum of the numbers is..." and he whispers the sum to BB.
Then AA says, "The product of the numbers is..." and he whispers the product to CC.
After that following conversation takes place :

BB:
"CC, I don't think that we know the numbers."
CC:
"Aha!, now I know the numbers."
BB:
"Oh, now I also know the numbers."
DD:
"Now, I also know the numbers."

How did they know the numbers?
-my answer is shorter than the old post. I listed it below.

所有跟帖： 

• 回复：answer -yma16- ♀ (1734 bytes) () 07/02/2003 postreply 22:01:00

• re-check... -puzzle4u- ♀ (107 bytes) () 07/02/2003 postreply 22:12:00

• Great work,I also -Atom9- ♀ (310 bytes) () 07/02/2003 postreply 22:24:00

• One more answer -yma16- ♀ (479 bytes) () 07/03/2003 postreply 12:46:00