1. **State the problem:** A scuba diver is at a depth of $-80\frac{1}{2}$ feet and ascends to the surface, which is at 0 feet. We need to find how many feet the diver ascended. 2. **Understand the depth:** The depth is given as a negative number because it is below the surface. The depth is $-80\frac{1}{2}$ feet, which can be written as $-\left(80 + \frac{1}{2}\right) = -80.5$ feet. 3. **Formula used:** The distance ascended is the difference between the surface level and the diver's depth. $$\text{Distance ascended} = 0 - \left(-80.5\right)$$ 4. **Calculate the distance:** $$0 - \left(-80.5\right) = 0 + 80.5 = 80.5$$ 5. **Interpretation:** The diver ascended $80.5$ feet to reach the surface. **Final answer:** The scuba diver ascended **80.5** feet.