Solve for the Unknown — Two Subtractions in a Row Find the value of “?” if 4003 − ? − 1599 = 716.

Introduction / Context:
This linear arithmetic equation involves an unknown subtracted in sequence. Rearranging carefully avoids sign mistakes. Such items appear frequently in aptitude tests to check manipulation of simple equations and attention to order of operations with subtractions.

Given Data / Assumptions:

• Equation: 4003 − ? − 1599 = 716.
• All numbers are integers.
• Goal: solve for ?.

Concept / Approach:
Group known terms first: (4003 − 1599) − ? = 716. Compute the bracketed difference, then isolate ?. Alternatively, move terms to opposite sides while keeping track of signs: 4003 − 1599 − 716 = ?. Both methods yield the same result when done correctly.

Step-by-Step Solution:
1) Compute 4003 − 1599 = 2404.2) Now 2404 − ? = 716.3) Rearranged: ? = 2404 − 716.4) Subtract: 2404 − 716 = 1688.

Verification / Alternative check:
Plug back: 4003 − 1688 − 1599 = (4003 − 1688) − 1599 = 2315 − 1599 = 716, confirming the solution.

Why Other Options Are Wrong:
1598 and 1692 come from digit errors in subtraction; 3120 results from misordering operations; “None of these” is wrong because 1688 is correct.

Common Pitfalls:
Forgetting that subtraction is not associative; performing 1599 − 4003 by mistake; mis-borrowing in the column subtraction.

Final Answer:
1688