One of the first things we learn when checking a variable is within a given range is that we can't use this form: 0 < n < 100. Mainly due to the order of operands. Since (0 < n) computes into a boolean value which incidentally (at least in Java) cannot be compared with an integer. Although, if you are using C it would compile since it treats booleans as 0 or 1. However, the second part of the test would make the whole expresion true all the time.
The way we tend to write this in code is with something in the line of this: (n > 0 && n < 100) which makes sense but we can do better. I think this notation is clearer: