Additional Rules

Advantage and Disadvantage
Sometimes an ability check, attack roll, or saving throw
is modified by special situations called advantage and
disadvantage. Advantage reflects the positive circumstances
surrounding a d20 roll, while disadvantage
reflects the opposite. When you have either advantage or
disadvantage, you roll a second d20 when you make the
roll. Use the higher of the two rolls if you have advantage,
and use the lower roll if you have disadvantage.
For example, if you have disadvantage and roll a 17 and
a 5, you use the 5. If you instead have advantage and roll
those numbers, you use the 17.
More detailed rules for advantage and disadvantage
are presented in chapter 7.

Specific Beats General
This book contains rules, especially in parts 2 and 3,
that govern how the game plays. That said, many racial
traits, class features, spells, magic items, monster abilities,
and other game elements break the general rules in
some way, creating an exception to how the rest of the
game works. Remember this: If a specific rule contradicts
a general rule, the specific rule wins.
Exceptions to the rules are often minor. For instance,
many adventurers don’t have proficiency with longbows,
but every wood elf does because o f a racial trait. That
trait creates a minor exception in the game. Other
examples of rule-breaking are more conspicuous. For
instance, an adventurer can’t normally pass through
walls, but some spells make that possible. Magic
accounts for most of the major exceptions to the rules.

Round Down
There’s one more general rule you need to know at the
outset. Whenever you divide a number in the game,
round down if you end up with a fraction, even if the
fraction is one-half or greater.