Silly math question

[Thespianus]

This is silly, but it caused some controversy at the gaming table last night:

A number of spells have effects like "+1 to X per three levels".

How is this calculated?

I assumed this meant that one would get X bonus like this:

Caster levels 1-3 -> +1 to X
Caster levels 4-6 -> +2 to X
etc

However, another player said that the math should be:
Caster levels 1-2 -> +0 to X
Caster levels 3-5 -> +1 to X
Caster levels 6-8 -> +2 to X
etc

Am I wrong?

[Thajocoth]

This is silly, but it caused some controversy at the gaming table last night:

A number of spells have effects like "+1 to X per three levels".

How is this calculated?

I assumed this meant that one would get X bonus like this:

Caster levels 1-3 -> +1 to X
Caster levels 4-6 -> +2 to X
etc

However, another player said that the math should be:
Caster levels 1-2 -> +0 to X
Caster levels 3-5 -> +1 to X
Caster levels 6-8 -> +2 to X
etc

Am I wrong?

Unless otherwise specified, you always round down for all division. However, I would recommend using "minimum 1" for something like that...

So:
Caster levels 1-2 -> +0 to X
Caster levels 3-5 -> +1 to X
Caster levels 6-8 -> +2 to X
Caster levels 9-11 -> +3 to X
Caster levels 12-14 -> +4 to X
etc

but what I would do is:
Caster levels 1-5 -> +1 to X
Caster levels 6-8 -> +2 to X
Caster levels 9-11 -> +3 to X
Caster levels 12-14 -> +4 to X
etc

[Edwin]

It means that you add X every time you have three y, which in this case means levels. However, generally, you always have a minimum of +1X, because having +0X in regards to range would be rather silly, when X is feet.

This is in most cases weighed out by the fact that a spell requires a certain level to cast, I.E. third for second level spells, effectively making +1X pr three levels mean x=Y/3.

So yes, at third level you have 1X, at sixth you have 2X, at ninth you have 3X and so on.

Edit: Ninja'ed by a far better, and more understandable actually, explanation - listen to him instead.

[Thespianus]

Ok, thanks both of you.

Drat, I just lost 1D6 of Sneak Attack from Hunter's Eye.

[kamikasei]

Unless otherwise specified, you always round down for all division. However, I would recommend using "minimum 1" for something like that...

This will usually be stated in the description, and if it's not, it's probably best not to add it unless you suspect it was an oversight.