Well, I can't answer you, since I don't have the points, but here.
If there's an odd number of terms, organize them from least to most, and kinda just move your fingers along to the middle, and they'll eventually meet at 1 term.
If there is an even number of terms, organize them from least to most, do the same thing, but this time, you'll get two different numbers at the middle. Add those two numbers, then divide by two, and you'll have your answer!
Good luck!
