In English, 'The half' is not used in sentences very much, and is mostly shortened to just 'half' , therefore, 'half' as an answer should also be accepted!
Agreed. This is an example of the stupid literalism sometimes (though inconsistently) applied here, to the detriment of linguistic authenticity.
Agreed! I even thought about writing "the half," but I I know that in Portuguese, you must often use the definite article in situations that wouldn't require it in English.