The following are negative number indicator rules
There are two valid negative number indicators: - (minus sign) and ( ) (parentheses).
- The minus sign must appear before the string of digits (and its unit character, if any)
- The parentheses must enclose the string of digits (and its unit character, if any)
- There may be any number of blank spaces between the minus sign and the string of digits (and special unit character if any) and between either of the parentheses and the string of digits (and special unit character if any).