diff --git a/course/en/chapter13/grpo_finetune.ipynb b/course/en/chapter12/grpo_finetune.ipynb similarity index 100% rename from course/en/chapter13/grpo_finetune.ipynb rename to course/en/chapter12/grpo_finetune.ipynb diff --git a/course/en/chapter13/grpo_format.py b/course/en/chapter12/grpo_format.py similarity index 100% rename from course/en/chapter13/grpo_format.py rename to course/en/chapter12/grpo_format.py diff --git a/course/en/chapter13/grpo_length.py b/course/en/chapter12/grpo_length.py similarity index 100% rename from course/en/chapter13/grpo_length.py rename to course/en/chapter12/grpo_length.py diff --git a/course/en/chapter13/grpo_math.py b/course/en/chapter12/grpo_math.py similarity index 100% rename from course/en/chapter13/grpo_math.py rename to course/en/chapter12/grpo_math.py