Whole number

A whole number usually means an ordinary number like 0, 1, 2, 3, 4, 5, and so on. Fractions, decimals, and negative numbers are not whole numbers.

What is confusing is that some people say that zero is not a whole number. And some people say that negative numbers are whole numbers. So the real answer to what is a whole number is, that it depends on which book you are reading or which teacher you have. That is why some people say "non-negative integers" instead of whole numbers, so everybody will know that they are including zero, and not including negative numbers.