This is an excellent question because many people are quite unsure how "whole" numbers are defined.
I was taught that whole numbers are counting number including zero. So whole numbers are 0, 1, 3, 4, 5, etc.
However, some people believe that because the term is "whole" number - it actually should include all numbers that are "whole" and not fractions or decimals. Hence, with this definition, it means that both negative and positive integers can also be whole numbers - such as -1, -2, -3, etc.
But the classic definition of whole number is: "Counting numbers including zero".