“the 1st” or “1st”

Question

I'm wondering which is the right usage between "the 1st" and "1st" in these sentences:

a) The United States ranked 1st in Bloomberg's Global Innovation Index.

b) The United States ranked the 1st in Bloomberg's Global Innovation Index.

I've seen a) in the news, however, it is like I've learned the definite article ('the') is required before an ordinal number (1st, 2nd, etc.)

Thank you.

Answer 1

You're right, in your example, sentence (a) is heard in the news, and it is also correct, but 'the first' is used in cases like:

She was the first woman to become Prime Minister.

and when talking about events like the Olympics where medals are awarded for those places:

He was the first over the line.
He was the first from his nation to win a medal in that sport.
The first-place winner is Mo Farah, from Great Britain.

Answer 2

I think a better rule is that when the ordinal is used as an adjective, an article is generally required:

He was the first person to land on the moon.

The green Camaro was the first car over the finish line.

With that, they became the third university to have over 1000 students.

When the ordinal number is used as an adverb, however, no article is called for:

The USA is ranked first in the survey.

I finished third.

John went fifth.