How can I prove that a complete binary tree has $\lceil n/2 \rceil$ leaves? Given a complete binary tree with $n$ nodes. I'm trying to prove that a complete binary tree has exactly $\lceil n/2 \rceil$ leaves.
I think I can do this by induction.

For $h(t)=0$, the tree is empty. So there are no leaves and the claim holds for an empty tree.

For $h(t)=1$, the tree has 1 node, that also is a leaf, so the claim holds.
Here I'm stuck, I don't know what to choose as induction hypothesis and how to do the induction step.
If the statement you're trying to prove by induction is


  For all positive integers $n$, a complete binary tree with $n$ nodes has $\lceil{n/2}\rceil$ leaves.


then the induction hypothesis must be


  For all positive integers $k&lt;n$, a complete binary tree with $k$ nodes has $\lceil{k/2}\rceil$ leaves.


Similarly, if the statement you're trying to prove by induction is


  For all positive integers $n$, a hoosegow with $n$ whatsits has $2^{\lfloor\sqrt{n}\rceil!}\cdot n^\pi$ nubbleframets.


then the induction hypothesis must be


  For all positive integers $k&lt;n$, a hoosegow with $k$ whatsits has $2^{\lfloor\sqrt{k}\rceil!}\cdot k^\pi$ nubbleframets.