1st Fill the 5-litre bowl, pour water from it to fill the 4-litre bowl, which you empty afterwards. pour the remaining 1 litre to the 4-litre bowl. Refill the 5-litre bowl and pour water from it to fill the 4-litre bowl (where there is already 1 litre). Thus you are left with 2 litres in the 5-litre bowl.
2nd The same principle - this time from the other end. Fill the 3-litre bowl and pour all of the water to the 4-litre bowl. Refill the 3-litre bowl and fill the 4-litre bowl to the top. And there you have 2 litres in the 3-litre bowl.