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Question

Consider the equation: $14 \times 8 \div 12 + 64 - 2 = 108$
This equation is currently incorrect. By interchanging one pair of numbers within the equation, it can be made true.
Which pair of numbers should be swapped to balance the equation correctly?

The correct answer is
2, 12

The problem requires finding which pair of numbers to interchange in the given equation to make it true.

Analyzing the Equation and Options

The initial equation is: $14 \times 8 \div 12 + 64 - 2 = 108$ Let's evaluate the left side using the order of operations (PEMDAS/BODMAS): Parentheses/Brackets, Exponents/Orders, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).

  1. Multiplication: $14 \times 8 = 112$
  2. Division: $112 \div 12 = \frac{112}{12} = \frac{28}{3}$
  3. Addition: $\frac{28}{3} + 64 = \frac{28}{3} + \frac{192}{3} = \frac{220}{3}$
  4. Subtraction: $\frac{220}{3} - 2 = \frac{220}{3} - \frac{6}{3} = \frac{214}{3} \approx 71.33$

Since $\frac{214}{3} \neq 108$, the equation is incorrect. We need to test swapping pairs of numbers.

Testing Number Swaps

Swapping 2 and 12 (Option C)

If we swap the numbers 2 and 12, the equation becomes:

$14 \times 8 \div 2 + 64 - 12 = 108$

Let's evaluate this new equation:

  1. Multiplication: $14 \times 8 = 112$
  2. Division: $112 \div 2 = 56$
  3. Addition: $56 + 64 = 120$
  4. Subtraction: $120 - 12 = 108$

The result is 108, which matches the right side of the original equation. Therefore, swapping 2 and 12 makes the equation true.

Verifying Other Options (Briefly)

Testing other swaps confirms they do not result in 108:

  • Swap 2, 8: $14 \times 2 \div 12 + 64 - 8 = 28 \div 12 + 56 = \frac{7}{3} + 56 = \frac{175}{3} \neq 108$
  • Swap 8, 14: $8 \times 14 \div 12 + 64 - 2 = 112 \div 12 + 62 = \frac{28}{3} + 62 = \frac{214}{3} \neq 108$
  • Swap 12, 14: $12 \times 8 \div 14 + 64 - 2 = 96 \div 14 + 62 = \frac{48}{7} + 62 = \frac{482}{7} \neq 108$

Conclusion

Swapping the numbers 2 and 12 balances the equation.

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Important Questions from Bodmas Rule

  1. The value of 90 ÷ 20 of 6 × [11 ÷ 4 of {3 × 2 - (3 - 8)}] ÷ (9 ÷ 3 × 2) is:

  2. The value of 1800 ÷ 20 × {(12 - 6) + (24 - 12)} is:

  3. The value of 20 ÷ 5 of 8 × [9 ÷ 6 × (6 - 3)] - (10 ÷ 2 of 20) is:

  4. The value of \(\left( {18 \div 2\;of\frac{1}{4}} \right)\; \times \;\left( {\frac{2}{3} \div \frac{3}{4}\; \times \;\frac{5}{8}} \right) \div \left( {\frac{2}{3} \div \frac{3}{4}of\frac{3}{4}} \right)\) is:

  5. The value of 18 ÷ [26 - {25 - (15 - 5) ÷ 2}] of 12 + 2 - 2 ÷ 4 × 16 is:

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