Approximation and quick calculation: Evaluate 26.823 × 27.923 × 4.5001 and select the closest option (use sensible rounding/estimation where appropriate).

Difficulty: Easy

Correct Answer: 3400

Explanation:


Introduction / Context:
This approximation problem tests number sense and the ability to round sensibly to get a near-exact product quickly. By grouping close-to-integer factors and using small adjustments, you can arrive at a highly accurate estimate without long multiplication.


Given Data / Assumptions:

  • Expression: 26.823 * 27.923 * 4.5001
  • Answer choices are coarse (hundreds-level), so a near-integer rounding is appropriate.
  • Select the closest option to the true value.


Concept / Approach:
Round each factor to a convenient nearby value, compute, and then refine if needed. Because options are spaced by 50–400, rounding to 27, 28, and 4.5 or using a tighter pair like 26.8 and 27.9 still lands very close to the exact product. Use compensations only if choices are close together.


Step-by-Step Solution:

Approximate 26.823 ≈ 26.8 and 27.923 ≈ 27.9; 4.5001 ≈ 4.5 Compute first product: 26.8 * 27.9 ≈ (27 * 28) − small ≈ 756 − small ≈ about 748 Multiply by 4.5: 748 * 4.5 ≈ 3366 Using a slightly tighter calc, the exact value is about 3370.48 (for reference), so the nearest listed option is 3400.


Verification / Alternative check:
Use midpoint method: (26.823 * 27.923) ≈ 27.373 * 27.373 ≈ 749.3; then 749.3 * 4.5001 ≈ 3371.9. Again, closest to 3400.


Why Other Options Are Wrong:

  • 3500 and 3450: Slightly high versus the refined estimate near 3370.
  • 3100: Too low given both partial estimates.
  • None of these: A reasonable close option exists (3400).


Common Pitfalls:
Over-rounding one factor too far (e.g., 30) without compensating others can push the product well above the true range. Keep rounding balanced across factors.


Final Answer:
3400

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