extra 2 bit shift in the adder ad which normally operates on a normal format a residual 2 bit shift must be retained for the three numbers x o a 1 sup y 1 and a 2 sup y 2 so that 2 low weight digits can be removed from the 18 bits or digits for instance in the case of numbers e g y 1 and y 2 which exceed the format receivable by the adder ad 16 bits the timing amplitude provided by the routers ag1 and ag2 is so chosen that such numbers have the receivable format i e that the amplitude of such timing is less than the amplitude of the readjustment which should normally be made and that the lowest weight of the readjusted number corresponds not to the weight of the units but to a greater weight for instance and as seen in the foregoing example in the case of 18 bit numbers a readjustment of 10 bits could normally be provided actually they will be readjusted by only 8 bits and the lowest weight will be equal to a weight of 2 2 4 conversely in the case numbers e g x o not exceeding the format receivable by the adder ad a shift is made by means of a router which is not shown of an amplitude such that the lowest weight bit of such number corresponds to the same weight as the lowest weight bit of numbers exceeding the format for instance in the previous example x o would be given a 2 bit adjustment so that its lowest weight bit takes the.