1. **State the problem:** We have two barrels with volumes given in different units: Barrel A has 6,800,000 mm³ of water, and Barrel B has 0.066 m³ of water. We need to find which barrel contains more water by converting volumes to the same unit. 2. **Formula and unit conversion:** To compare volumes, convert mm³ to m³ using the conversion factor: $$1\text{ m} = 1000\text{ mm} \implies 1\text{ m}^3 = (1000\text{ mm})^3 = 1,000,000,000\text{ mm}^3$$ 3. **Convert Barrel A volume to m³:** $$\text{Volume in m}^3 = \frac{6,800,000\text{ mm}^3}{1,000,000,000} = 0.0068\text{ m}^3$$ 4. **Compare volumes:** - Barrel A: $0.0068\text{ m}^3$ - Barrel B: $0.066\text{ m}^3$ Since $0.066 > 0.0068$, Barrel B contains more water. 5. **Other methods to compare volumes:** - Convert Barrel B's volume to mm³ by multiplying by $1,000,000,000$ and compare directly. - Use liters as a common unit since $1\text{ m}^3 = 1000\text{ liters}$ and $1\text{ liter} = 1000\text{ cm}^3$. - Use a physical measuring tool or container to measure volumes if possible. **Final answer:** Barrel B contains more water than Barrel A.