1. Let's clarify the problem: You asked how the number 54 was obtained. 2. To explain this, I need to know the original expression or calculation that led to 54. 3. For example, if 54 came from multiplying 6 by 9, the formula used is multiplication: $$6 \times 9 = 54$$. 4. If it was from adding numbers, say 27 and 27, then addition was used: $$27 + 27 = 54$$. 5. Please provide the original problem or expression so I can show the detailed steps and reasoning.