diff --git a/part10/README.md b/part10/README.md
index f08ee4f..50a317c 100644
--- a/part10/README.md
+++ b/part10/README.md
@@ -1,5 +1,5 @@
-Part 9
-======
+Part 10
+=======
 
 ## Installation
 
diff --git a/part11/README.md b/part11/README.md
index 50a317c..3c33eb9 100644
--- a/part11/README.md
+++ b/part11/README.md
@@ -1,4 +1,4 @@
-Part 10
+Part 11
 =======
 
 ## Installation
diff --git a/part12/README.md b/part12/README.md
index f01b7a8..7fcc3c3 100644
--- a/part12/README.md
+++ b/part12/README.md
@@ -1,4 +1,4 @@
-Part 11
+Part 12
 =======
 
 ## Installation
diff --git a/part13/part12/README.md b/part13/part12/README.md
index deddbd0..3b4c4bb 100644
--- a/part13/part12/README.md
+++ b/part13/part12/README.md
@@ -1,4 +1,4 @@
-Part 12
+Part 13
 =======
 
 ## Installation
diff --git a/part9/README.md b/part9/README.md
index 7f690df..f08ee4f 100644
--- a/part9/README.md
+++ b/part9/README.md
@@ -1,4 +1,4 @@
-Part 8
+Part 9
 ======
 
 ## Installation