Identify the odd number: In most three-digit numbers listed, the third digit equals the sum of the first two digits (ab + c rule). Choose the number that does NOT follow this property.
Verbal Reasoning
Classification
Difficulty: Medium
Choose an option
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A527
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B639
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C246
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D356
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ENone of these
Answer
Correct Answer: 356
Explanation
Introduction / Context:This classification item uses a digit-based rule. For most options, the ones digit equals the sum of the hundreds and tens digits. One number fails this pattern; identify it.
Given Data / Assumptions:
- Numbers: 527, 639, 246, 356.
- Interpretation: For XYZ, check whether Z = X + Y.
Concept / Approach:Break each number into digits and test the sum relation.
Step-by-Step Solution:
527 → 5 + 2 = 7 → matches.639 → 6 + 3 = 9 → matches.246 → 2 + 4 = 6 → matches.356 → 3 + 5 = 8, but last digit is 6 → violates.Verification / Alternative check:Compute (last digit) − (sum of first two digits). Only 356 gives 6 − 8 = −2, confirming the mismatch.
Why Other Options Are Wrong:They satisfy the defined digit-sum condition exactly.
Common Pitfalls:Misreading digits or adding incorrectly (e.g., 3 + 5 mistaken as 6). Carefully parse each digit before adding.
Final Answer:356 is the odd number.