PL/SQL can use an interpreter to run code.
set serveroutput on
declare
v_length_nr NUMBER :=5.5;
v_width_nr NUMBER :=3.5;
v_area_nr NUMBER;
begin
v_area_nr:=v_length_nr*v_width_nr;
DBMS_OUTPUT.put_line('Area:'||v_area_nr);
end;
/
SET SERVEROUTPUT ON turns on the communication channel from the database back to the client session.