Compared to what? You can improve accuracy by optimising the way you do your calculations. A really trivial example: 10000 + .00001 - 10000 is less accurate th

Compared to what? You can improve accuracy by optimising the way you do your calculations. A really trivial example: 10000 + .00001 - 10000 is less accurate than 10000 - 10000 + .00001. Without interval arithmetic, you can't easily measure this and decide which way round is best.