SQL>
SQL>
SQL> CREATE OR REPLACE FUNCTION add_three_numbers( a NUMBER := 0, b NUMBER := 0, c NUMBER := 0 ) RETURN NUMBER IS
2 BEGIN
3 RETURN a + b + c;
4 END;
5 /
Function created.
SQL>
SQL> BEGIN
2 dbms_output.put_line(add_three_numbers(3,4,5));
3 END;
4 /