Base conversion — convert the decimal value to binary. Task: Express 18₁₀ as a binary number (no prefixes or suffixes).
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A11110
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B10001
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C10010
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D1111000
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E010010
Answer
Correct Answer: 10010
Explanation
Introduction / Context:Converting decimal to binary is a fundamental skill for understanding memory layouts, bitwise operations, and low-level protocols. The standard approach decomposes a number into sums of powers of two or uses repeated division by 2.
Given Data / Assumptions:
- Decimal value: 18
- Unsigned, positive integer
Concept / Approach:Find the largest power of two not exceeding 18, subtract it, and continue until the remainder is zero. Alternatively, perform successive dividing by 2 and record remainders from least significant to most significant bit.
Step-by-Step Solution:
Powers of two: 16, 8, 4, 2, 118 = 16 + 2 ⇒ bits for 16 and 2 are 1; others 0Binary pattern: 1 (16) 0 (8) 0 (4) 1 (2) 0 (1) ⇒ 10010Verification / Alternative check:Using division by 2: 18/2=9 r0, 9/2=4 r1, 4/2=2 r0, 2/2=1 r0, 1/2=0 r1; remainders upward give 10010. Convert back: 10010₂ = 16 + 2 = 18₁₀, confirming correctness.
Why Other Options Are Wrong:
- 11110: equals 30₁₀.
- 10001: equals 17₁₀.
- 1111000: equals 120₁₀.
- 010010: correct value with a leading zero; while numerically same, the canonical minimal form is 10010.
Common Pitfalls:
- Misplacing weights (confusing the 8 and 4 positions).
- Dropping necessary zeros between set bits.
Final Answer:10010