Knowledge: The real meaning of a cellphone is to communicate with someone who is far away. On the other hand, number 7 represent harmony and luck.

Conversation:
7 has always been my favorite number. It's very lucky for me.
Seven is the natural number between 6 and 8.
Yes, I know. Do you know the real meaning of number 7?

Response: Oh, the real meaning of number 7 is harmony and luck.