Here's a (very rough half-baked) idea.
Advantage and Disadvantage
From time to time, special circumstances can give you an advantage or a disadvantage when attempting to perform an action. Climbing a cliff in the driving rain is more difficult, while striking an enemy while they are prone is easier.
The rules will sometimes tell you that you have advantage or disadvantage. This will be accompanied by a number, know as the degree of advantage or disadvantage--for example, higher ground might give you advantage 5 while climbing that slippery cliff might inflict disadvantage 16.
If you have advantage, and you roll the degree indicated or lower on your d20, you may reroll the die and take the higher of the two rolls. Conversely, if you have disadvantage and you roll the degree indicated or higher on your d20, you must reroll the die and take the lower of the two numbers.
Advantage and disadvantage usually come in the forms of advantage 5 and advantage 10, and disadvantage 16 and disadvantage 11.
If two or more effects grant you advantage 5 or better, you instead have advantage 10. If two or more effects inflict disadvantage 16 or worse, you instead have disadvantage 11.
Advantage and disadvantage cancel each other out on a one-for-one basis, irrespective of the degree of advantage or disadvantage.
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Doing the maths on this, Advantage 10 is about equal to a +5, Advantage 5 is about equal to a +2.5, Advantage 2 is about equal to a +1. There are some weird probability curve things on it at the extremes though.
Advantage and Disadvantage
From time to time, special circumstances can give you an advantage or a disadvantage when attempting to perform an action. Climbing a cliff in the driving rain is more difficult, while striking an enemy while they are prone is easier.
The rules will sometimes tell you that you have advantage or disadvantage. This will be accompanied by a number, know as the degree of advantage or disadvantage--for example, higher ground might give you advantage 5 while climbing that slippery cliff might inflict disadvantage 16.
If you have advantage, and you roll the degree indicated or lower on your d20, you may reroll the die and take the higher of the two rolls. Conversely, if you have disadvantage and you roll the degree indicated or higher on your d20, you must reroll the die and take the lower of the two numbers.
Advantage and disadvantage usually come in the forms of advantage 5 and advantage 10, and disadvantage 16 and disadvantage 11.
If two or more effects grant you advantage 5 or better, you instead have advantage 10. If two or more effects inflict disadvantage 16 or worse, you instead have disadvantage 11.
Advantage and disadvantage cancel each other out on a one-for-one basis, irrespective of the degree of advantage or disadvantage.
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Doing the maths on this, Advantage 10 is about equal to a +5, Advantage 5 is about equal to a +2.5, Advantage 2 is about equal to a +1. There are some weird probability curve things on it at the extremes though.