The Seder seems to be all about the number four – the four questions, the four sons, the four cups, the four expressions of redemption.
But, if we look closer, the fours, are actually all fives.
There is a fifth question, which we don’t say, a fifth cup – the cup of Eliyahu (Elijah), the fifth expression of redemption of heveiti (he will bring us [to the Land of Israel]).
But where is there a fifth child?