If you want to say that the middle does not include both or the middle includes both, you
If you want to say that the middle does not include both or the middle includes both, you can only put brackets around it. Parentheses (excluding xx) are also common in junior high schools, which generally have explanations and are not ambiguous.
It is best to write it as an integer from 0.5 to 2.5, so there will be no ambiguity.