لاحظ فقط
...................................1*8 + 1 = 9
.................................12*8 + 2 = 98
...............................123*8 + 3 = 987
.............................1234*8 + 4 = 9876
...........................12345*8 + 5 = 98765
.........................123456*8 + 6 = 987654
.......................1234567*8 + 7 = 9876543
.....................12345678*8 + 8 = 98765432
...................123456789*8 + 9 = 987654321