1. **State the problem:** Convert 450 milliliters (mL) to liters (L). 2. **Recall the conversion factor:** 1 liter (L) = 1000 milliliters (mL). 3. **Set up the conversion:** To convert mL to L, divide the number of milliliters by 1000. 4. **Calculate:** $$450 \text{ mL} = \frac{450}{1000} \text{ L} = 0.45 \text{ L}$$ 5. **Interpretation:** 450 milliliters is equal to 0.45 liters.