SQL & PL/SQL

Hey all,Can someone clear my doubt on trunc..here is the example

SQL> select trunc(45.923,2) from dual;

TRUNC(45.923,2)
===============
	  45.92

SQL> select trunc(12345.5432,2) from dual;

TRUNC(12345.5432,2)
===================
	      12346

In the first example oracle truncates the number to 2 decimal places so the value is 45.92..But,whereas in the second one it should do the same..The result should resemble 12345.54...But,oracle gives me *12346*..
Can someone explain me the reason why it does like that

Thanks in advance!!