Three positions of a dice are given below. Identify the number on the face opposite to 6.

On the basis of following pattern in given dices , we can say that
The numbers 2, 4, 5 and 6 cannot be on the face opposite to 3.
The numbers 1, 3, 4 and 6 cannot be on the face opposite to 5.
Therefore, 2 lies opposite 5.
Clearly, 4 lies opposite 6.