83 is the answer. Just add! (:
The sum is 64
The sum of 99 and 64 is 163.
19 plus 19 is 38
The factors of 64 are 1, 2, 4, 8, 16, 32 and 64. No two of them add up to 19.
5 + 19 = 24
64
135
The sum is 481
5 + 8 + 20 + 12 + 19 = 64
GCF = 4, sum = 84.
3 + 19 + 25 + 307 = 354
19.