1, 2, 3, 4, 5 and 6 have written on surface of a dice. Four forms of a dice shown below. In this dice, which digit will be on the surface opposite to the digit 6.

3

On comparing, figure ‘II’ and ‘III’,  ‘3’ is common

then from '3' move in clockwise direction in figure 'II' as well as in figure 'III' we get,

In figure (II) and (III) 

⸫ 3 is opposite to 6

1 is opposite to 4

2 is opposite to 5