When you say “Sum ____”, the description you include of each term is *each* term. For example:

“Sum each number” S x = 1 + … + n

“Sum each square” S x^2 = 1^2 + … + n^2

If it helps you remember, the capital S is just the initial of Sum.

Other than that, yes, you have described the sum correctly. The point is to describe it *instead of* fully writing it down.