Ask how many more liters of water must be poured into the tank to fill the tank

Lesson 5: A rectangular water tank has dimensions in the tank: length 5 m, width 2 m and depth 1,2 m. Currently, the tank is holding of the water tank. Ask how many more liters of water must be poured into the tank to fill the tank (knowing that 1dm3 contains 1 liter of water)