For an integer represented in a fixed-radix number system, a number formed by replacing each digit d in the integer by its complement, i.e. by
(R − 1 − d)
where R denotes the radix of the system. For example, in the decimal system the nine's complement of 0372 is 9627; in the binary system the one's complement of 1100 is 0011. See also complement number system, radix complement.