Which representation uses the first bit as the sign and the remaining bits as the magnitude for signed numbers?

• A. Sign-Magnitude Form
• B. Two's Complement
• C. One's Complement
• D. Floating Point

Answer: (A)

This is sign-magnitude form. In this scheme, the most significant bit acts as the sign flag: 0 means positive, 1 means negative. The remaining bits simply give the magnitude—the absolute value of the number. For example, with one sign bit and three magnitude bits, +3 would be represented as 0 011 and -3 as 1 011. The value is read by taking the magnitude bits as a positive number and applying the sign from the first bit.

This fits the description exactly because the sign and the magnitude are separate fields. It’s different from two's complement and one's complement, where the sign is not a separate magnitude field—the value is derived from a pattern that encodes negatives differently (inverting bits and adding one, or using a full two's-complement rule). Floating point also isn’t this scheme, since it uses an exponent and a significand, not a direct sign bit plus magnitude bits for the value.