Working odd summer jobs has been 'the sum of' my experience so far. [=has been all the experience I've had so far]
That picture 'sums' him 'up' perfectly. [=that picture perfectly shows what kind of person he is]
“So, you don't want to go because you think it will be boring?” “That just about 'sums it up'.”
(..) He did it mechanically. Now I understand why the American lost to Perez and the bald guy. He wasn't really losing, but paying a large sum that way. What are you going to do? Get angry a bit! Who's it? You're just on time. Calm down, Choucas! (..)1981 To Kill a Cop