To convert cups to quarts, you need to know the conversion factor: 1 quart = 4 cups.
To convert 9 cups to quarts, you divide the number of cups by the number of cups in a quart:
\[ 9 \text{ cups} \div 4 \text{ cups/quart} = 2.25 \text{ quarts} \]
This can also be expressed as a mixed number. The whole number part is 2, and the remaining part (0.25) can be expressed as \(\frac{1}{4}\):
So, 2.25 quarts is \(2 \frac{1}{4}\) quarts.
Thus, 9 cups of chicken stock is equivalent to 2.25 quarts or \(2 \frac{1}{4}\) quarts.