title: ORA-06502: PL/SQL: numeric or value error when concatenating
body: <pre><code>DECLARE
      a NUMBER;
      b NUMBER;
  BEGIN
      a :=: a;
      b :=: b;
      DBMS_OUTPUT.PUT_LINE('sum = '|| a+b);
  END;
  </code></pre>
  <p>I am getting error as numeric or value error</p>