A machine-implemented method converts a number from a first base to a second base. Each one of a first group of machine operation computes a product whose factors include the number in the first base, and a previously calculated approximation to a respective negative power of the second base. A second group of machine operations are performed, each one using results of the first operations, to obtain further results. A respective one or more digits of the number in the second base is also determined, using each of these further results. Other embodiments are also described and claimed.