Difficulty: Easy
Correct Answer: 1011001₂
Explanation:
Introduction / Context:Converting between decimal (base 10) and binary (base 2) is a foundational skill in digital electronics and computer architecture. The question asks for the binary representation of 89₁₀. Understanding this helps with addressing, masking, and low-level data manipulations.
Given Data / Assumptions:
Concept / Approach:The standard approach is repeated subtraction (or division by 2 remainders) using powers of 2. Express 89 as a sum of distinct powers of 2, then place 1s in those bit positions and 0s elsewhere. Highest power of 2 not exceeding 89 is 64 (2^6).
Step-by-Step Solution:
Identify powers: 89 - 64 = 25 → bit for 2^6 is 1. Next: 25 - 16 = 9 → bit for 2^4 is 1 (2^5 = 32 is too large, so bit 2^5 is 0). Next: 9 - 8 = 1 → bit for 2^3 is 1. Remaining: 1 → bit for 2^0 is 1. Bits for 2^2 and 2^1 are 0. Assemble bits from 2^6 to 2^0: 1 0 1 1 0 0 1 → 1011001₂.Verification / Alternative check:Compute 1011001₂ back to decimal: 64 + 16 + 8 + 1 = 89. This confirms correctness.
Why Other Options Are Wrong:
1011011₂ = 64 + 16 + 8 + 2 + 1 = 91 (not 89). 1100111₂ = 64 + 32 + 4 + 2 + 1 = 103 (not 89). 10011₂ = 16 + 2 + 1 = 19 (too small). “None of the above” is incorrect because a correct option exists.Common Pitfalls:Dropping leading zeros is fine, but do not drop necessary middle zeros; confusing the order of bits or mis-summing powers of 2 causes off-by-one errors.
Final Answer:1011001₂
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