Simple equation: solve for the missing addend If 9873 + x = 13200, find the value of x.

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