There are different definitions of "whole numbers".
Some define it as an integer (i.e. positive or negative) [some dictionaries]
Some define it as a non-negative integer. [most math definitions]
We will take the math definition, i.e. 0<= whole number < ∞
To find pairs (i.e. two) whole numbers with a sum of 110, we start with
0+110=110
1+109=110
2+108=110
...
54+56=110
55+55=110
Since the next one, 56+54=110 is the same pair (54,56) as 54+56=110, we stop at 55+55=110 for a total of 56 pairs.
