Simple plsql program 3

DECLARE
a integer := 10;
b integer := 20;
c integer;
f number(10,2);
f1 number;
BEGIN
c := a + b;
dbms_output.put_line('Value of c: ' || c);
f := 70.0/3.0;
dbms_output.put_line('Value of f: ' || f);
f1 := a*b;
dbms_output.put_line('Value of f: ' || f1);

END;