When a statistic is modified it can never go above double its base value.
If results are divided and leave fractions, always round down except in the case of distances, where fractions of inches are kept.
Numerical values of traits can be modified.
If an effect requires dice to be substituted, the value of the dice is often fixed to some value. It is helpful to physically remove the dice and place it, showing that value, with the dice that were rolled.
If a dice is substituted, it cannot be re-rolled.
If modifiers, rerolls, adding or removal of dice affect any roll then only after all of these have been resolved can a result be determined.