diff --git a/bintree.c b/bintree.c
index cd4571a..1e34db0 100644
--- a/bintree.c
+++ b/bintree.c
@@ -189,5 +189,9 @@ void clearTree(TreeNode *root)
 // Returns the number of entries in the tree given by root.
 unsigned int treeSize(const TreeNode *root)
 {
-
+    if (root == NULL) {         //0 for end
+        return 0;
+    }
+    return 1u + treeSize(root->left) + treeSize(root->right); //using 1u to insure unsigned
+    //recursively adds entries in the tree after root to left and right
 }
\ No newline at end of file