Choose symbol sequence — Replace * to balance: 7 * 7 * 2 * 1 = 12

Difficulty: Medium

Correct Answer: + - x

Explanation:

Introduction / Context:We must select a fixed sequence of three operators to make the equation true. Standard precedence applies.

Given Data / Assumptions:

  • Template: 7 {s1} 7 {s2} 2 {s3} 1 = 12.

Concept / Approach:Test reasonable combinations; subtraction and multiplication often help reach small targets like 12.

Step-by-Step Solution:

Option B (+ - ×): 7 + 7 - 2 × 1 = 14 - 2 = 12 → true.Other options do not yield 12 under precedence.

Verification / Alternative check:Explicitly compute each alternative; only Option B balances.

Why Other Options Are Wrong:

  • They produce values like 47, 12 by chance only if precedence is ignored, or other mismatches.

Common Pitfalls:

  • Ignoring that × takes precedence over +/−.

Final Answer:+ - x

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