Andre is cutting fence boards from a large piece of wood 10 1/4 yards long. Each board needs to be 4/5 yard. How many whole, equal-sized boards can he cut from this piece of wood?

To find how many boards Andr- can cut, we need to divide the length of the piece of wood by the length of each board: $\dfrac{10 \frac{1}{4}}{\frac{4}{5}}$. Because division by a fraction is the same as multiplying by its reciprocal, we have $\dfrac{10 \frac{1}{4}}{\frac{4}{5}}=10 \frac{1}{4} \cdot \dfrac{5}{4}=\dfrac{41}{4} \cdot \dfrac{5}{4}= 10.25 \cdot \dfrac{5}{4}=\boxed{12.8125}$. André can cut 12 whole, equal-sized boards from this piece of wood.