meaning of "An estimated"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hi,

I don’t understand the use of ‘an’ in the following sentnece. Which noun does it apply to?

[color=blue]The victims were among an estimated 300000 ethnic Koreans from China who now live in South Korea.

Thanks,

MG.

2

Hi,

We use ‘an’ here because ‘estimated’ starts with a vowel sound and I assume that it refers to an understood word like ‘figure’ as in: an estimated figure of ***

Alan

3

Thanks.