As the description of the algorithm is largely based on practice, we leave a complete description to the references. We mention only that (1) the red number is the result approximated to a selected number of decimal places and (2) brown numbers are obtained by duplicating the current red number and appending a suitable digit to extend the computation. We separate the digits into pairs, starting from the right. Beginning with the leftmost pair of digits we obtain the current blue numbers by multiplying the current red and brown values and subtracting the result from the old blue value in a manner resembling long division.