Spayed means a female dog has had her reproductive organs (ovaries and uterus) removed. Neutered means technically that an animal has been de-sexed, but usually is used to refer to a male dog being castrated.
A complement is a word or word group. that completes the meaning of a. verb. Every sentence has a subject. and a verb. Sometimes the subject. and the verb can express a. complete thought all by themselves.
Because of these convenient properties two's complement is most common method to represent negative numbers on computers. P.S. Inverse code, or one's complement, complements binary code to, (all ones). It also can be used to represent negatives, but addition scheme should employ cyclic carry and is more complex.