As a learner, "as ... as" is always a little confusing. Say somebody said the following.
You should do at least as good a job as them.
Now I can understand how there is a noun between two as's, but I've never fuĺly understood how to use articles when using "as ... as". If I were to say something like that, I'd go for this.
You should do an at least as good job as them.
What's the underlying rule of "as ... as" that makes the first usage correct?
Edit: I think I may need to elaborate on what I'm confused about in detail. (Sometimes even describing what I'm confused about is hard to say. Please excuse me :( )
When it comes to the example sentence, the way my mind works is like first, I take the basic form without "as ... as", such as
You should do at least a good job.
Then I try to change it by inserting "as ... as" before and after the adjective, including the following few nouns ("good job" in this case). But this definitely does not work for this sentence.
You should do at least an as good job as them.
I only know this is not correct because I've never heard of this kind of usage. Seeing the correct usage in the first example sentence, I think the correct way to go is moving the article ("a") together with the noun ("job") after the adjective ("good"), but I wasn't sure when and how I should relocate the words that were in front of the adjective to behind of it.