Three different positions of the same dice are shown, the six faces of which are numbered from 1 to 6. Select the number that will be on the face opposite to the one showing '6’.

3

Step 1) In figure 2  and 3

Step 2) Compare both the figure and we find out 1 and 2 both are common

Step 3)  Therefore 3 is the number which will be opposite to 6