The dotted die is shown in positions (i), (ii) and (iii). In position (iv) the top face is hidden. How many dots are on that top face?

1 is seen with 2, 4, 5 and 6, so 1 is opposite 3; 2 is seen with 1, 4, 6 and 3, so 2 is opposite 5; and 4 is opposite 6. The top in (iv) must touch both 5 and 1, so it is 4 or 6. Picture (ii) shows the corner of 1, 5 and 6, but there the faces go round in the order 1, 6, 5, while (iv) has 5 then 1 in the other direction. So (iv) shows the other corner of 1 and 5, the one with 4.