It depends on how the value got into your pgm. If you defined it as a literal (with the decimal point) then pnk079 is correct.
If the value was read from a file (with the decimal point) or passed by another pgm via CALL, etc. then you must define the PIC as 9(14).9999. You must then move it to another field defined as 9(14)V9999.
This eliminates the decimal point clearing the way for you to successfully perform arithmetic operations on the field.