My only guess is that they assume people will be confused by 3-digit (or fewer) results. They could have coerced it to a string, though, which yields pretty goo

My only guess is that they assume people will be confused by 3-digit (or fewer) results. They could have coerced it to a string, though, which yields pretty good results: (Math.floor(Math.random() * 10000) + 10000 + "").substr(1)