R SRR i 62 SPECIAL TOPICS IN THEORETICAL ARITHMETIC Other examples in change of radix: 365(°P) = 101101101(2) = 11231(4) = 555(8) = 16110) 1398('f) = 21043(5) 3312(4) = 246(F) 3312(10) = 13074(*) 212013(4) = 2439(f) = 987(0) 124. For changing from the sexidenal scale to the quater- nary we can derive a simple rule. In the first place the digits and radix of the sexidenal scale are represented as follows in the quaternary scale: 0=0 4 =10 8 =20 © =30 0 = 100 1=1 S5=11 9 =21 e =31 2 =2 Boa 12 P =22 ¥ = 32 3=3 =13 0 =23 ¢ =33 Consider the number 90 2 (0), which equals DX U X D42, 9 X 102 = 21 X 1002(4) = 21,00,00 (4) O X110 =23X100(4) = 23,00 (4) 2 = 31 (4) Hence 902 (I0) = 21,23,31 (4) The rule evidently is to substitute for the digits of the number written in the sexidenal scale their representations in the quater- nary scale, each occupying a period of two figures. The period of two figures is due to the fact that [0 is the second power of 4. As another example, 3924(10) = 3, 21 02,10(4). 125. We can in just the same way change from the quater- nary scale to the binary, because 4 is the second power of 2. For this change 2 is replaced by 10 and 3 by 11. For example, 231(4) = 10,11,01(2) 21,23,31(4) = 10,01,10,11,11,01(2)