I'm preparing for academic IELTS by writing some essays and then correcting those using a grammar correction app.
In the following sentence,
Overall, carbohydrates prevail in both dishes, especially speaking about the second one, which contains more than a half of those.
The app suggests deleting "a" before "half" which results in "...contains more than half of those". But considering the fact that "half" is a countable noun, why there doesn't have to be an article then?