from
The Free On-line Dictionary of Computing (8 July 2008)
positional representation
<mathematics> The conventional way of writing numbers as a
string of digits in which each digit, D, has value D * R^I,
where R is the {radix} or (number) base and I is the digit's
position counting leftward from zero at the least significant
(right-hand) end. Each digit can be zero to R-1. Each
position has a weight or significance R times greater than the
position to its right and the right-most place has a weight of
one.
Decimal numbers are radix ten, {binary} numbers are radix two,
{octal} radix eight and {hexadecimal} radix 16.
Positional representation makes arithmetic operations on large
numbers much easier than, say, {roman numerals}. It is
fundamental to the binary representation used by {digital
computers}.
(2006-11-10)