9
The sum is: 8
It is: 8+1+7 = 16
The sum of 1/8 and 3/8 is 1/2
The sum of the numbers given is 31. 1 + 2 + 4 + 8 + ... + 2n = 2n+1 - 1
The sum of 1/2 and 5/8 is 1 1/8
3/8 + 1/8 = 1/2
The sum of -7 and -8 is -15.
The sum of 7 and -8 is -1.
The sum of 8/9 and 4/7 is 1 29/63.
The sum of 10 plus 8 is 18.
The sum of 1/8 and 3/8 is 1/2
-1