Why are binary and decimal called positional numbering systems?
The traditional number system is called a positional number system. A number is represented as a string of digits. Each digit position has a weight associate with it. Number’s value is equal to a weighted sum of the digits
In mathematical numeral systems, the base or radix is usually the number of unique digits, including zero, which a positional numeral system uses to represent numbers. For example, for the decimal system the radix is 10, because it uses the 10 digits from 0 through 9.
In mathematics and digital electronics, a binary number is expressed in the base-2 numeral system or binary numeral system, which uses only two symbols 0 (zero) and 1 (one).
since, these systems are called as positional number system.