declare
v_number_grade number:=:number_grade;
v_letter_grade char(1);
begin
if v_number_grade>100 then 
dbms_output.put_line('notele sunt pana la 100!!');
else
v_letter_grade:=
case 
 when (v_number_grade>=90 and v_number_grade<=100) then 'A'
 when v_number_grade>=80 then 'B'
 when v_number_grade>=70 then 'C'
 when v_number_grade>=60 then 'D'
else 'F'
end;
end if;
dbms_output.put_line(v_letter_grade);
end;


