"The sum of A and B," "A added to B," "A plus B," "the total of A and B ..." - but, as **JamesM** posted, not "the sum of A added to B." That could only be correct in a broader context, such as "the sum of A added to B and C added to D," which would mean (A+B)+(C+D). Arithmetically, that's exactly the same as A+B+C+D, but there are situations in which we might want to speak of the two intermediate sums.