Approximation and quick calculation: Evaluate (421 × 0.9) + (130 × 101) + 10000 and select the closest option.

Introduction / Context:This blends a small decimal scaling with an easy product and a large constant. Compute each piece separately, then sum. Option spacing (thousands) allows a quick precise pick without heavy computation.

Given Data / Assumptions:

• 421 * 0.9
• 130 * 101
• + 10000

Concept / Approach:Use 0.9 = 1 − 0.1 to scale down 421 quickly, multiply 130*101 using 130*(100+1), then add 10000. This keeps the arithmetic mental and exact to the unit place if desired.

Step-by-Step Solution:

Verification / Alternative check:Rounding 378.9 to 379 gives 23509; still nearest to 23500 compared to 24500 or 33500.

Why Other Options Are Wrong:33500 and 24500 deviate by thousands; 225000 is two orders of magnitude too large.

Common Pitfalls:Multiplying 130*101 as 130*100 only and forgetting the additional 130; or treating 0.9 as 1.0 inadvertently, adding an extra ~42 to the sum.

Final Answer:23500