What it one fifth plus one fifteenth?

Well, isn't that just a happy little math problem we have here! To find the sum of one fifth and one fifteenth, we need to make the denominators the same. We can do this by finding a common denominator, which in this case is 15. So, one fifth is equivalent to three fifteenths, and when we add that to one fifteenth, we get four fifteenths. Just like that, we've painted a beautiful little math equation!