Petals Around the Rose

Petals Around the Rose: ?

Problem

The challenge is to determine the rule used to calculate the number above from the dice shown. Your only clues are the name of the game and the fact that the rule must be fairly simple, able to be calculated at a glance if someone knows it.

You may reroll the dice as many times as necessary until you are sure you know the rule. Be careful though: you may only have one opportunity in your lifetime to solve the problem yourself, so be certain you are ready before clicking Reveal Solution.

Solution

Definitions:

A rose is the center pip on a die face.
A petal is any pip on the outer edge.

The Rule:

The number shown is the total number of petals (edge pips) on dice with a rose (center pip).

Explanation:

Only odd numbered faces can contribute to the total, but not all of them do. Going case by case:

1 has a rose, but no petals, so contributes nothing.
3 has a rose and a petal on each side so contributes 2.
5 has a rose and a petal each corner so contributes 4.

The even numbered faces (2, 4, and 6) do not have a center pip, so contribute nothing to the total.

Now that you have revealed the answer petals will be shown in red; you may reroll to see other examples.