1. **State the problem:** We are given the number of plates for stacks 2, 3, 4, and 5, and we need to find the missing number of plates for 1 stack. 2. **Identify the pattern:** The plates correspond to multiples of 11 per stack number. This means the number of plates is calculated by the formula: $$\text{Plates} = 11 \times \text{Stacks}$$ 3. **Apply the formula:** For 3 stacks, the number of plates is: $$11 \times 3 = 33$$ 4. **Find the missing value for 1 stack:** Using the formula: $$11 \times 1 = 11$$ 5. **Conclusion:** The missing value for 1 stack is 11 plates. This matches the pattern and confirms the formula is correct.