706.2 After the roll, the number indicated on the top face of the die before any modifiers is the natural result. The instruction may include modifiers to the roll which add to or subtract from the natural result. Modifiers may also come from other sources. After considering all applicable modifiers, the final number is the result of the die roll.
706.2a
Modifiers may be optional and/or have associated costs. If a modifier has an associated mana cost, the player who rolled has the chance to activate mana abilities before applying it.
706.2b
If two or more effects are attempting to modify the natural result, the player who rolled chooses one to apply, following these steps: First, consider any effects that modify the result of a die roll by rerolling that die. Second, consider any effects that modify the result of a die roll by increasing or decreasing that result by a specified amount.