- Fill the 5-liter jug completely.
- Pour water from the 5-liter jug into the 3-liter jug until the 3-liter jug is full, leaving exactly 2 liters in the 5-liter jug.
- Empty the 3-liter jug, and then pour the remaining 2 liters from the 5-liter jug into the 3-liter jug.
- Fill the 5-liter jug again and carefully pour water into the 3-liter jug until it’s full. This leaves exactly 4 liters in the 5-liter jug.