TOPIC: Approximate and approximately

Could someone please advise which word of them is the correct one below:
Question : We should use “approximate” or “approximately”
1. Regarding the assessment for the approximate 2,600 nos. schools, it is concluded that XXXXXXXXXXXXXXXXXXXX.
2. Regarding the assessment for the approximately 2,600 nos. schools, it is concluded that XXXXXXXXXXXXXXXXXXXXX.

1. Regarding the assessment for the approximate 2,600 nos. schools, it is concluded that ...
2. Regarding the assessment for the approximately 2,600 nos. schools, it is concluded that ...
Sentence 2 is correct because “approximately” is used before a number or amount, and “approximate” is used before a noun or after BE.
To understand more about how their usage varies, I suggest you look at the concordances for these two words at www.edict.com.hk/default.htm.