Comparator is being dumb

So okay basically the comparator of I put one redstone dust into the back where the redstone torches are then it should output one correct? Well no it is deciding to output 15 when I input one which continues on with 2 = 14 3 = 13 4 = 12 5 into 11 6 into 10 7 into 9 8 into 8 7 into 9 and so on up until 15 again which is strange it should output whatever I put in in comparison mode no? I don't have any other redstone connections either just a straight line now subtraction mode which is surprisingly worse if I put 3 input in the back and 10 input in the side nothing should happen yet it subtracts so the comparator is thinking 3-10 =7 which shouldn't be possible yet it works but if I try to it the normal way 10 into the back the redstone torches and three into the sides it doesn't subtract my brain doesnt understand I've tried to fix it with videos I've tried new worlds I've even tried breaking and re putting the blocks just absolutely nothing