Explanation:

Let's analyze the problem step by step and check each option to make the equation correct:

- Original equation: 81 + 45 ÷ 3 - 18 × 9 = 32.

- Applying PEMDAS/BODMAS rule:

- First, divide: 45 ÷ 3 = 15

- Then, multiply: 18 × 9 = 162

- The equation becomes: 81 + 15 - 162 = -66, which is incorrect.

- Option 1: Swap 81 and 18.

- New equation: 18 + 45 ÷ 3 - 81 × 9

- Becomes: 18 + 15 - 729 = -696, incorrect.

- Option 2: Swap 45 and 18.

- New equation: 81 + 18 ÷ 3 - 45 × 9

- Becomes: 81 + 6 - 405 = -318, incorrect.

- Option 3: Swap 3 and 9.

- New equation: 81 + 45 ÷ 9 - 18 × 3

- Becomes: 81 + 5 - 54 = 32, correct.

- This option works!

- Option 4: Swap 45 and 9.

- New equation: 81 + 9 ÷ 3 - 18 × 45

- Becomes: 81 + 3 - 810 = -726, incorrect.

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