It's the sum of 42 and 13 which is 55.
20
The sum of j and 13 can be represented as j + 13. In mathematics, the sum is the result of adding two or more numbers together. Therefore, the sum of j and 13 is j + 13.
19
the sum of 67 + 13 = 80
13.
6 + 7 = 13(Sum means add)
10
The sum of the first 13 odd numbers is 169.
-13
26
n + 13