Die rolls are written as XdY. * X = represents the number of dice rolled * Y = represents the highest face-value of the die (the lowest value is 1) For example, 4d8 means four 8-sided (values between 1 and 8 inclusive) dice are rolled (giving a weighted random number of 4-32). When the number of dice is not indicated, it means one die is rolled; e.g. d20 means 1d20. The d100 is sometimes written as d% or d00 and is also referred to as percentile dice.