I'm so confused about something maybe others think it as simple as it but I find it hard to manipulate and treat with ..along my analysis.

lets assume I want to calculate the sum of integers then, I can define variable like this X is sum of integers, and there's another cosmetics naming which I can define it as sum(integers).

what's confusing me is " sum(integers) " is at the end variable like X but the "()" is annoying me and what's the behind concept of using () in the naming containers?! is using () while naming variables affecting my solution analysis?