I don't quite understand how to use table 12-3: CR Equivalencies in the CRB. In the example below it, they don't seem to adjust the CR based on the quantity. So, when and how do I use it?
Two CR's of the same level adjust the total CR by 2.
As an example 2 CR 7 monsters =CR 9
3 CR 7 monsters =CR 10
And the pattern keep goings.
That table helps you to determine the XP value of a certain number of creatures.
Example: A CR 1 creature is 400 xp. The chart says that two creatures are CR + 2. CR + 2 = CR 3, which is 800 xp.
Then why in the example of the Stone Giant and the Gargoyles do they not apply it?
It says the budge allows 9,600. A CR8 Stone Giant is 4,800, leaving 4,800 for the gargoyles. They say that leaves room for four gargoyles who are 1,200 apiece...Oh wait, I just saw the math. I thought that four 1,200 added 4,800 because there were four of them and 4 * 1,200 is the 4,800. But, it is basing it off of 12-3. What a dummy.
So, it only actually doesn't effect CR more than just adding them together.
The chart shows easy calculations. The reason it skips some numbers (between 4 and 6, for example) is because 5 creatures of one CR does not equal a new CR.
Basically: you should only use the table if you're trying to quickly calculate the xp total of a group of monsters in an encounter.
An encounter's CR is determined by the sum total of all creatures' xp values.
So, it only actually doesn't effect CR more than just adding them together.
Precisely. Pathfinder redid XP to work this way. They include both methods of calculating CR so that people who were used to the 3.5 method would know that it was acceptable to continue using it.