So as long as y is positive, this makes the sum greater than the difference For example, if x = 10 and y = 2, then x+y = 10+2 = 12 x-y = 10-2 = 8 clearly 12 > 8 is true
If y is some negative number (say y = -4), then x+y = 10+(-4) = 10-4 = 6 x-y = 10-(-4) = 10+4 = 16 and things flip around
Saying a blanket statement "the sum of two integers is always greater than their difference" is false overall. If you require y to be positive, then it works but as that last example shows, it doesn't always work.
So to summarize things up, I'd say the answer is "no, the statement isn't true overall"