*Key Point*: Don't memorize these relations between Internal nodes and leaf nodes. It varies as per definition of degree. So go by definition in question **ONLY**.

Like if "Degree is # of children of a node" than its **n _{2}=n_{0}-1** ( where n

_{2}is # Internal nodes having degree 2 & n

_{0}is # leaves with degree 0)

And if "Degree is # of neighbors of a node" than its** n _{3}=n_{1}-2** ( where n

_{3}is # Internal nodes having degree 3 & n

_{1}is # leaves with degree 1)