PA0465 Console Scientific Calculator Program

                                                      
   Parentheses can be used in calculations if they are
   inserted on either side of the operand fields. Due 
   to limitations imposed by a 68 column display there
   can be no parentheses surrounding the last operand 
   field. Parentheses can be entered either by typing 
   them in at the appropriate field or by interrupting
   under that field. An error will be displayed if    
   parentheses are improperly nested.