And we find several times the ordinal number without the noun that it is modifying, in particular in a place where the noun that it modifies was already said in the beginning, like ויחטאהו כראשון (and offered it for sin, as the first)¹⁵⁴.

footnotes: ¹⁵⁴ Leviticus 9:15.

And when it is written כאשר שרף את הפר הראשון (as he burned the first bullock)¹⁵⁵, there is a homiletical interpretation.

Leviticus 4:21 says,והוציא את הפר אל מחוץ למחנה ושרף אתו כאשר שרף את הפר הראשון חטאת הקהל הוא (And he shall carry forth the bullock without the camp, and burn it as he burned the first bullock; it is the sin-offering for the assembly). Why did it mention the wordהפר, meaning the bullock, a second time, when it could have just saidהראשון*, meaning the first? This is to teach that the bullock comes first and not the idolatry goats¹⁵⁶.*

footnotes: ¹⁵⁵ Leviticus 4:21. ¹⁵⁶ Malbim, HaTorah v’HaMitzvah Vayikra 255.