Solve $1599 \div 39.99 + \frac{4}{5} \times 2449 - 120.05 = x$

Concept & Strategy This is an approximation problem, signaled by the complex decimals and widely spaced answer choices. Round decimals to their nearest whole numbers to drastically speed up calculation while maintaining sufficient accuracy. Step-by-Step Solution * Approximate the given values to their nearest integers: $1599 \approx 1600$ $39.99 \approx 40$ $2449 \approx 2450$ $120.05 \approx 120$ * Rewrite the equation using BODMAS rules (Division and Multiplication before Addition and Subtraction): $$1600 \div 40 + \frac{4}{5} \times 2450 - 120 = x$$ * Perform the division: $$1600 \div 40 = 40$$ * Perform the multiplication: $$\frac{4}{5} \times 2450 = 4 \times 490 = 1960$$ * Substitute the results back into the simplified equation: $$40 + 1960 - 120$$ $$2040 - 120 = 1880$$ Exam Strategy & Shortcut Recognize the approximation cues instantly. $1599 \div 39.99$ is intentionally designed to look ugly but perfectly rounds to $1600 \div 40 = 40$. Treat $\frac{4}{5} \times 2449$ as $\frac{4}{5} \times 2450$. Mentally calculate $2450 \div 5 = 490$, then $490 \times 4 = 1960$. Add $40$ to get $2000$, and drop the $120$. The entire problem can be mapped out mentally in under 15 seconds. Common Pitfall Attempting to calculate exact values (like finding the precise result of $\frac{4}{5} \times 2449 = 1959.2$) wastes immense amounts of time and creates messy decimals that often lead to addition/subtraction errors in the final steps. Never do exact math on an approximation question. Final Answer Therefore, the correct answer is **1880**.