All true, but they do not add up to the whole.
Here all of them together do not add up to one.
Maybe you can make two and one add up to eight.
The numbers 3, 6 and 9 add up to 18.
But do they add up to too great a price?
But does all this add up to a children's book?
Do two men perhaps add up to one whole person?
Maybe I needed a good rest, but in my mind all the little things just don't add up to the big thing.
Even a small change can add up to big numbers.
Many small things can add up to a big one.