plsql中关于包的问题！求解释

Question

create or replace package wan123
is
procedure jiayou(
firstnumber number,
secondnumber number,
jieguo out number);
end wan123;
create or replace package body wan123
is
procedure jiayou(
 firstnumber number,
 secondnumber number,
 jieguo out number)
is 
begin
  jieguo=firstnumber+secondnumber;
end;
以上是创建的一个包，为甚总是显示Encountered the symbol "CREATE" 错误

Answer 1

--package
create or replace package wan123
is
procedure jiayou(
firstnumber number,
secondnumber number,
jieguo out number);
end wan123;--package body
create or replace package body wan123
is
procedure jiayou(
  firstnumber number,
  secondnumber number,
  jieguo out number)
is
begin
   jieguo:=firstnumber+secondnumber;
   end;
end wan123;

Answer 2

人家1楼不写给你了吗，当人家不存在呀jieguo=firstnumber+secondnumber;
错在这，应是赋值:=而不是=jieguo:=firstnumber+secondnumber;