This question is intended only for those familiar with some basic Kabbalistic concepts.
As we know (from יהו"ה), that ו (Vav, number 6) stands for Z"A (masculine) and ה (He, number 5) stands for Malchus (feminine).
However, the Written Torah - that is Z"A - has 5 books, where the Oral Torah - that's Malchus - has 6 Sdarim.
How come?