You can connect 35 of these 40 colored lights in series, the other 5 in parallel with any of these 35, and then connect them to the 220V lighting circuit. The reason is that the rated voltage of each lantern is 6.3V, 35 lanterns in series are exactly 220V, and the other five lanterns are connected in parallel, and the voltage of each lantern does not exceed 6.3V, so it can be used normally.
The calculation formula of electricity consumption is kWh, the power of each lantern is 0.5W, and 40 lanterns are used at the same time, which is 20W. The electricity consumption for two hours is 40Wh, which is 0.04 kWh, which is 0.04kWh..