Naming Benzene-1,2-dicarboxylic acid (Phthalic acid)

[Isaac Denton 1C]

On page 65 of Introduction to Organic Chemistry phthalic acid is named Benzene-1,2-dicarboxylic acid. I'm having trouble with the numbering of the carbons. I'm assuming the numbering is given to the carbons in benzene. How do we number the carbons? If the numbering of the carbons start in benzene, why isn't the molecule named Benzene-1,6-dicarboxylic acid?

Here's a line structure of Benzene-1,2-dicarboxylic acid https://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Phthalic_acid_ACS.svg/512px-Phthalic_acid_ACS.svg.png

[Mary Anastasi]

You are correct in that the carbons in the ring itself are the numbered ones, not the carbons that are part of the carboxyl groups. Since the carboxylic acids are attached to carbons that are connected to each other, number one of them 1 and the other 2. It doesn't matter which direction you number in.