Difficulty: Medium
Correct Answer: 10100101
Explanation:
Introduction / Context:Several binary signed-number schemes exist: sign-magnitude, one's complement, and two's complement. In sign-magnitude, the most significant bit (MSB) encodes the sign (0 = positive, 1 = negative), and the remaining bits encode the magnitude as an ordinary unsigned number. This question asks for −37 in 8-bit sign-magnitude form.
Given Data / Assumptions:
Concept / Approach:
First convert the magnitude to binary using as many lower bits as needed (here 7 magnitude bits). Then set the MSB to 1 to indicate a negative number. No inversion or addition is performed in sign-magnitude (contrast with two's complement).
Step-by-Step Solution:
Convert 37 to binary: 37 = 32 + 4 + 1 → bits → 00100101 (8-bit view).Extract the 7-bit magnitude: 0100101 (from the lower 7 bits of 00100101).Set MSB as sign = 1 for negative.Form final 8-bit word: 1 (sign) + 0100101 (magnitude) = 10100101.Verification / Alternative check:
Check that the magnitude portion equals 00100101 when viewed as 8 bits with MSB cleared, and that the sign bit is 1. No complements are involved in sign-magnitude.
Why Other Options Are Wrong:
00100101: sign bit 0 → +37, not −37.
11011000 or 11010001: these patterns do not represent −37 in sign-magnitude; they resemble unrelated bit patterns and, if interpreted as two's complement, would encode different values.
Common Pitfalls:
Confusing sign-magnitude with two's complement (which requires inverting and adding 1), or forgetting that only the MSB encodes the sign while the magnitude stays uninverted.
Final Answer:
10100101
Discussion & Comments