1. **State the problem:** We have a large rectangle divided into 20 small squares (5 rows × 4 columns). Each small square has an area of $9\text{ cm}^2$. Among these, 11 squares are shaded, and we need to find the area of the rectangle that is unshaded. 2. **Formula and rules:** The total area of the rectangle is the sum of the areas of all small squares. The unshaded area is the total area minus the shaded area. 3. **Calculate total area:** $$\text{Total area} = 20 \times 9 = 180\text{ cm}^2$$ 4. **Calculate shaded area:** $$\text{Shaded area} = 11 \times 9 = 99\text{ cm}^2$$ 5. **Calculate unshaded area:** $$\text{Unshaded area} = \text{Total area} - \text{Shaded area} = 180 - 99 = 81\text{ cm}^2$$ 6. **Answer:** The area of the rectangle that is unshaded is $81\text{ cm}^2$.