The most accurate approximate arithmetic is done by using convergent iteration. An iteration to divide by 3 is based on the identity a/3=a/2-(1/2)(a/3) Approximate a/3 by a/2 and repeat (new a/3) = a/2 - (old a/3) /2. until (new (new a/3)) == old a/3 The iteration converges rather fast. Notice that you need to compare results over two iterations to "filter" the last bit oscillation. In the same way you can divide by 5 by iteration based on identity a/5=a/4-(1/4)(a/5) etc. -- Lauri --- For more info.