VMS Help FORTRAN, Data, Constants, REAL_4  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  A REAL*4 constant can be a basic real constant (with or without a
  decimal exponent) or an integer constant followed by a decimal
  exponent.  A basic real constant has one of these forms:

     s.nn                s is an optional sign
     snn.nn              nn is a string of decimal digits
     snn.

  A decimal exponent has the form:

     Esnn                s is an optional sign
                         nn is an integer constant