x = (1.234567890125, 1.2345678901255) print x print x[0], x[1] >>> (1.2345678901249999, 1.2345678901254999) >>> 1.23456789012 1.23456789013 Is there a rational reason, or is that simply an artifact of the way that the code has evolved? It is clearly not a bug :-) Regards, Nick Maclaren.