From QB64 Wiki
The - mathematical operator performs subtraction on two numerical values or negates a single value.
Syntax: return_value = number1 - number2
- Numbers used can be any literal or variable numerical value type.
- Subtracting a negative value will actually perform addition with the other value.
- Subtracting a negative or negated value will make the return value more positive.
- Addition and subtraction are the last operations performed in Qbasic's normal order of operations.
- Subtraction cannot be performed on STRING values.
+ positive (addition operator)