Three different positions of the same dice are given. Find the number on the face opposite to the face showing '6'.

We can solve this using standard dice rules by comparing different positions:
Using the Two Common Faces Rule:
Compare Position 2 and Position 3:

* Both positions have two faces in common: 4 and 5.
* According to the established rule of dice, when two positions of the same dice have two faces in common, the remaining third faces on both positions are directly opposite to each other.
* In Position 2, the remaining face is 2.
* In Position 3, the remaining face is 6.

Therefore, the face opposite to 6 is 2.