According to Google, the three most common error codes from visiting a web site are 403, 404, and 500.
  1. Without knowing which error code is most common, express this set mathematically.
  2. Error code 500 is the most common. Error code 403 is the least common of these three. And that leaves 404 in the middle. Express the error codes in a mathematical way that appreciates how frequently they happen, from most often to least often.
  1. Since we only have to describe a collection of three numbers and their order doesn’t matter, we can write {403,404,500}.
  2. Now we must describe the same three numbers and we want readers to know that the order we are writing the numbers matters. We can write (500,404,403).