In the USA, the Internal Revenue Service is who you file your taxes (not make the declaration) with. Whether or not (those last two words are pleonastic, but I like them here) they are a competent organism depends entirely on (not of) your opinion. And it would be strange if they were called the Ranch and the official program for preparing your taxes (not the rent) were called Father.

You don’t discount things on your tax forms, but you can deduct them.

Rest is what you do after you get your taxes in. It doesn’t mean subtract.