Two positions of a dice are shown below. When three is at the top what number will be at the bottom?

As per the given pattern in question figure , we can find the similar next position of given dice .
Six dots are on the face adjacent to one dot, three dots, four dots and five dots.
So, two dots lie opposite six dots.
If we rotate the first dice downward two times, we get the second dice.
So, five dots lie opposite three dots.