-13 is already an integer. It corresponds to the absolute value 13.
-13 is an integer.
Integer.
13
-13 is rational and an integer.
13 is an integer and so there is no sensible way of writing it as a fraction or mixed number.
0.030 is not an integer. So there would be no integer for it.
-13/100
No, it is an integer.
2x + 1 is equal to or less than 13.
13 is an integer and so the answer is 13 months, or k*13/k moths where k is any non-zero integer. There is nothing in the question requiring the measurement unit to be changed and, in any case, the answer would depend on whether the unspecified unit was a week or a year (or something else).
To the nearest integer, 13
Yes, all negative whole numbers, including -13, are integers.