The missile knows where it is, because it knows where it isn't. And by subtracting where it isn't from where it is, the missile finds out where it needs to go (or sum like that it's been a minute since ive seen that meme)
*inhale* the missile knows where it is at all times it knows this because it knows where it isn't by subtracting where it is from where it isn't or where it isn't from where it is whichever is greater and it goes on
