There are 2 containers, 5 and 8 liters. How to use them to collect 7 liters of tap water?

In order to collect 7 liters of tap water into a container, you need:

5 container we collect water, pour from it into an 8 liter container;

An 8 liter container lacks another 3 liters of water, we collect 3 liters into a 5 liter container and pour 3 liters into an 8 liter container, 2 liters of water remain in a 5 liter container, pour out of 8 liter water and pour 2 liters of water from a 5 liter container and again collect a 5 liter container and also pour it into an 8 liter one.

We get 2 + 5 = 7 liters of tap water in an 8 liter container.