The packed keyword is only legal for set, array, record, object, class and file types. In contrast to the 16-bit version of Delphi, packed will affect the layout of record, object and class types.

program Produce;
type
  SmallReal = packed Real;
begin
end.

Packed can not be applied to a real type - if you want to conserve storage, you need to use the smallest real type, type Single.

program Solve;
type
  SmallReal = Single;
begin
end.