Can somebody explain why double is being treated differently in the following code piece ? double d1= 33.30+33.40+33.30; double d2= 33.40+33.30+33.30; double d3= 33.30+33.30+33.40; Among these only d3 gives me result of 100.0 other 2 gives me 99.9.

This is a very old problem with floating point. If you want exact value you must use BigDecimal.

This is due to a limitation in the value you can represent on a bit pattern as there is an infinite number of decimal value between 0 and 1 there is a need for some imprecision.

Jean-Sebastien is, of course, absolutely right. The key two points are:

1. Floating point math is an *approximation* (integer and BigDecimal is *exact*) ... and ... 2. The order you perform the individual calculations affects what values the intermediate results round to, which in turn affects the final result.