Handle nested decimals and a complex division: Compute (.23 − .023) / (.0023 / 23) and choose the exact value.

Difficulty: Medium

Correct Answer: 2070

Explanation:


Introduction / Context:
This problem combines decimal subtraction with a division by a small decimal ratio, testing careful manipulation of place values and reciprocals.



Given Data / Assumptions:

  • Numerator: 0.23 − 0.023.
  • Denominator: 0.0023 / 23.
  • Perform exact arithmetic (no rounding required).


Concept / Approach:
First simplify the numerator. Then recognize that dividing by a small number is equivalent to multiplying by its reciprocal; compute the denominator exactly to avoid compounding decimal errors.



Step-by-Step Solution:

Numerator: 0.23 − 0.023 = 0.207Denominator: 0.0023 / 23 = 0.0001 (since 23 × 0.0001 = 0.0023)Overall value = 0.207 / 0.0001 = 2070


Verification / Alternative check:
Rewrite the compound fraction: (0.23 − 0.023) * (23 / 0.0023) = 0.207 * 10000 = 2070, the same result.



Why Other Options Are Wrong:
0.207 and 0.0207 ignore the denominator’s effect. 207 under-multiplies by a factor of 10. 20.7 is still short by two orders of magnitude.



Common Pitfalls:
Miscomputing 0.0023 / 23 or moving the decimal point incorrectly when dividing by a ten-thousandth.



Final Answer:
2070

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