Three different positions of the same dice are shown (figures 1 to 3)…

 

Step 1) In figure 1 and 3, 2 is common

Step 2) The number ‘2’ is common in both the dice, but it is at a different position. In order to find out, the number appearing on the opposite face, rotate the dice in a clockwise direction with the common number as the reference.

Step 3)  2     5     6

               2     4     1

Step 4)   4  is opposite to 5

               1  is  opposite  to 6

Therefore ,

2 is opposite to 3