Answer:
G. 1,494
Explanation:
We know that the special operation
gives the sum of all the whole numbers less than the number it operates on.
The example given by the question is:

where 3, 2, 1, and 0 are added because they are all of the whole numbers less than 4, which is the number that
operated on.
Now, to the problem at hand:
First, let's just show the expanded representations of each term in the expression:


I will call the terms within the parentheses subterms.
We can see that there is significant overlap between each term's subterms; actually, the entirety of
's subterms are within
. So, when we subtract the former from the latter, we are just left with the terms that aren't part of the overlap.
We can identify these non-overlapping subterms as:

which can be simplified to get the answer:
G. 1,494