-                        Subtraction and Negation

    Subtraction

 exp1 - exp2

    The - operator performs subtraction. If the expression involves
    operands of more than one precision, all operands are converted to the
    same level--that of the highest-precision operand in the expression--
    before the expression is evaluated.

   exp1,exp2    Any numeric expression.



    Negation

 - exp1

    As a unary operator (placed before a single numeric expression), -
    performs negation; that is, it reverse the sign of its operand.

        exp1    Any numeric expression.