To determine which number among −13, 0, or 13 is an integer but does not belong in either of the subsets of integers, we need to clarify the integer subsets typically considered. The two common subsets of integers are:
- Positive Integers: This subset includes numbers like {1, 2, 3, ...}.
- Negative Integers: This subset includes numbers like {..., -3, -2, -1}.
The number 0 is considered neither a positive nor a negative integer, so it does not belong in either of these subsets.
Thus, the answer is 0.