IQ level test

A man wanted to enter a club. Every member knew the password.
The man was hidden beside the wall & tried to listen the password.

A member came, watchman said '12'
Member replied 6.
Watchman opened the door.

Another member came, watchman said 6
Member replied 3.
Watchman opened the door.

Man thought he got the password.
He went at door, watchman said 8, Man replied 4. Watchman didnt opened the door.

What was the PASSWORD???
Guess the answer????