This method of computation works always, but is not as simple as for integers because Euclidean division is more complicated. Therefore, a third method is often preferred for hand-written computations. It consists in remarking that the norm of the greatest common divisor of and is a common divisor of , , and . When the greatest common divisor of these three integers has few factors, then it is easy to test, for common divisor, all Gaussian integers with a norm dividing .