On a basic level, all stories are about problem solving. Nearly every genre can fit into this basic mold.
Let me start with a few examples. In a romance the problem to solve is how to make a relationship work. In a sci-fi or fantasy, it’s usually about figuring out how to overcome some big external force. In literary fiction it will usually be more about how to deal with the different aspects of life in all their ugliness. And in a mystery it's often as simple as figuring out who did something and how they did it.
But like all problem solving, it’s only interesting when it’s complicated and fun. 1+1 is hardly a compelling problem for most people when asked for an answer, but often plots, especially the bad ones, will give us this sort of obvious math. Usually you can guess somewhat at where a plot can go next, but the good ones take us on a scenic path as we move toward the inevitable answers. Or perhaps they take us through a painful journey before giving us a beautiful answer we were hoping to find at the end.
So when writing a plot, stop and ask if it adds up. Do your characters and plot really create the end you're hoping for? Or is there something that needs to be added in earlier to help increment something so it makes sense later on? How do the characters relate to the problems they're trying to solve? What might the events of the book add or take away from their lives? Are they divided between tough choices while the complications and dangers around them multiply?
Maybe someday we could have a more precise formula for books, but maybe part of what makes them so interesting is that we don't. Until then, count the elements of your story more carefully than you count your words.