0 + other digit = other digit 9 + other digit = (other digit -1) + 1 = other digit I don't know if there is a good way to quantify this other than it is a bas

0 + other digit = other digit 9 + other digit = (other digit -1) + 1 = other digit I don't know if there is a good way to quantify this other than it is a basic property of base 10 when you are basically looping around the basis. The other post illuminates on this in that it would be E for hex or 5 for base 6.