How to report an bug in calculator

How do I report a bug or actually an error in the calculator that comes with Android? The version of Android on my Tab4 is 4.4.2 and 4.1.2 on my Samsung phone. It is the modulus function -- '%'. For example on paper if you divide 24 by 7 you get a remainder of 3, which is the correct modulus. The Android calculator puts a 'x' after the '%' and in front of the number you are trying to mod by. You end up with a 1.68. The only way this could be correct is if the creators of the calculator had something else in mind for the modulus symbol, which probably shouldn't be done. Maybe use '%x' on the button would be more accurate.