Simple equation: solve for the missing addend If 9873 + x = 13200, find the value of x.
Correct Answer: 3327
Introduction / Context:This is a straightforward linear equation with one unknown addend. Such problems appear frequently as warm-ups for algebraic manipulation and mental math.
Given Data / Assumptions:
- Equation: 9873 + x = 13200.
- We need x.
Concept / Approach:Isolate x by subtracting 9873 from both sides. This is the inverse operation to addition and yields the unknown directly.
Step-by-Step Solution:x = 13200 − 9873.Compute: 13200 − 9800 = 3400; subtract remaining 73 → 3400 − 73 = 3327.
Verification / Alternative check:Add back to confirm: 9873 + 3327 = 13200. Correct.
Why Other Options Are Wrong:3237 and 3337 reflect digit transpositions; “None of these” is incorrect because a valid option (3327) exists; 3427 overshoots by 100.
Common Pitfalls:Borrowing mistakes in subtraction; rushing and misplacing tens or hundreds.
Final Answer:3327