From the set of numbers: {1, 2, 3, 4, 5, 6}, how many different sums can be formed by summing up any two numbers in the set?$\displaystyle 6P2$=30.

I'm thinking this could be a permutation because 1+2 and 2+1 are not two different sums. So,

Is this correct? Or would it be a combination...