Difficulty: Easy
Correct Answer: 1100 1010 0110 0100
Explanation:
Introduction / Context:
Two’s complement is the dominant representation for signed integers in computer systems. It enables straightforward addition/subtraction using the same binary adder hardware. Converting a positive binary word to its two’s complement negative (or vice versa) uses a simple invert-plus-one recipe.
Given Data / Assumptions:
Concept / Approach:
The two’s complement of a binary word W is computed by inverting every bit (forming the one’s complement) and then adding 1 to the result. This effectively computes 2^n − W for an n-bit word, which represents the arithmetic negation modulo 2^n.
Step-by-Step Solution:
Verification / Alternative check:
Hex cross-check: 0011 0101 1001 1100 = 0x359C; two’s complement = 0xCA64. Adding 0x359C + 0xCA64 = 0x10000 (overflow ignored in 16 bits), confirming correctness.
Why Other Options Are Wrong:
Options a, b, and d differ by one or more bits; none equals the computed sum after the +1 step. Therefore option c is the unique correct result.
Common Pitfalls:
Forgetting the +1 after inversion, mishandling carries across grouped spaces, or inverting only up to the first 1 from the right (which is an alternative shortcut but easy to misapply).
Final Answer:
1100 1010 0110 0100
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