hindu–arabic numeral system|
- western arabic
- eastern arabic
non-standard positional numeral systems|
- bijective numeration (1)
- signed-digit representation (balanced ternary)
- mixed (factorial)
- complex-base system (2i)
- non-integer representation (φ)
- asymmetric numeral systems
list of numeral systems|
in digital numeral systems, the radix or base is the number of unique digits, including the digit zero, used to represent numbers in a positional numeral system. for example, for the decimal/denary system (the most common system in use today) the radix (base number) is ten, because it uses the ten digits from 0 through 9.
in any standard positional numeral system, a number is conventionally written as (x)y with x as the string of digits and y as its base, although for base ten the subscript is usually assumed (and omitted, together with the pair of parentheses), as it is the most common way to express value. for example, (100)10 is equivalent to 100 (the decimal system is implied in the latter) and represents the number one hundred, while (100)2 (in the binary system with base 2) represents the number four.