Common dice used in Role Playing is the following, with the number after the D representing the number of sides on the dice:
- D4
- D6
- D8
- D10
- D12
- D20
- D100
Other variants include D2 (typically a coin is used), D3, and D30. These variants and others can be made with the Black Dice App.
A common special case is percentile rolls, referred to as D100. Since actual hundred-sided dice are large ( and some studies have shown that 100 sided dice are not random ) , almost spherical, and difficult to read, percentile rolls are instead handled by rolling two ten-sided dice together, using one as the "tens" and the other as the "units". A roll of ten or zero on either die is taken as a zero, unless both are zeros or tens, in which case this is 100. Some sets of percentile dice explicitly mark one die in tens and the other in units to avoid ambiguity. (No need to worry about this, Black Dice handles this by displaying a number)
The number before the D represents the number of dice that are being thrown, so 3D6 would represent that three 6 sided dice are rolled and typically the sums are added together.
Modifiers change the roll, with Black Dice, you can change the roll by adding a modifier to every roll or you can choose to add a sum to the end of your rolls. Rolls that add a modifier to every sum is represented with it inclosed within (). So, for example, if you have a roll that rolls 2D4 (two 4 sided dice) and you're adding one to each roll, it's represented as follows:
(2D4+1) -- which comes out to, or is similar to adding the sums of two dice 1D4+1 and 1D4+1
This would generate a random number between 4 and 10. However, if you want to add a sum after making a roll, you can and it would be represented this way...
(2D4) + 2 -- which comes out to, or is similar to adding the sums of two 1D4 then adding two to the result.
Modifiers typically change the distribution of the rolls and the amount of "chance" in the rolls. This is why Role Playing Games (RPGs) use different rolls to produce different chances and different results depending on the circumstance.
This is essentially explains how the Black Dice App is to be used. If you want more interesting choices with "Custom" dice, check out this Wikipedia page: http://en.wikipedia.org/wiki/Dice#Rarer_variations. Have Fun!
