Closeness in any number system is defined by a metric. Using the 10-adic metric the distance between numbers and is given by . An interesting consequence of the 10-adic metric (or of a -adic metric) is that there is no longer a need for the negative sign. (In fact, there is no order relation which is compatible with the ring operations and this metric.) As an example, by examining the following sequence we can see how unsigned 10-adics can get progressively closer and closer to the number −1: