diff --git a/src/tree.py b/src/tree.py
index 9e6a5cf92c84709d1994acde622d49c591613017..b770efcbed27862e46454c98fa75f23c00da153b 100644
--- a/src/tree.py
+++ b/src/tree.py
@@ -119,7 +119,8 @@ class TreeWalker:
             level_path = os.path.join(self.root, level)
             num, config = self.load_level_node(level_path)
             levels.append((num, config))
-        levels.sort(key=lambda item: item[0])
+
+        levels = self.resort_children(self.root, levels)
         root_node["children"] = [item[1] for item in levels]
         return root_node
 
@@ -145,7 +146,7 @@ class TreeWalker:
                 num, chapter = self.load_chapter_node(full_name)
                 chapters.append((num, chapter))
 
-        chapters.sort(key=lambda item: item[0])
+        chapters = self.resort_children(base, chapters)
         level_node["children"] = [item[1] for item in chapters]
         return level_node
 
@@ -157,10 +158,21 @@ class TreeWalker:
                 num, section = self.load_section_node(full_name)
                 sections.append((num, section))
 
-        sections.sort(key=lambda item: item[0])
+        sections = self.resort_children(base, sections)
         chapter_node["children"] = [item[1] for item in sections]
         return chapter_node
 
+    def resort_children(self, base, children):
+        children.sort(key=lambda item: item[0])
+        for index, [number, element] in enumerate(children):
+            title = list(element.keys())[0]
+            origin = os.path.join(base, f"{number}.{title}")
+            posted = os.path.join(base, f"{index+1}.{title}")
+            if origin != posted:
+                self.logger.info(f"rename [{origin}] to [{posted}]")
+            os.rename(origin, posted)
+        return children
+
     def ensure_chapters(self):
         for subdir in os.listdir(self.root):
             self.ensure_level_config(subdir)