complementer
A digital circuit that computes the complement of a binary number; used in arithmetic logic units and computer design.
補数器は、減算を加算で行うために使われる。
A complementer is used to perform subtraction by addition.
Compound of 補数 (hosū, 'complement') + 器 (ki, 'device'). The term is a direct calque of English 'complementer'.