diff --git a/2021-fall/homeworks-practice/homework-practice-03-gd/homework-practice-03-gd.ipynb b/2021-fall/homeworks-practice/homework-practice-03-gd/homework-practice-03-gd.ipynb
index 0ee99e19..5a664a9d 100644
--- a/2021-fall/homeworks-practice/homework-practice-03-gd/homework-practice-03-gd.ipynb
+++ b/2021-fall/homeworks-practice/homework-practice-03-gd/homework-practice-03-gd.ipynb
@@ -532,7 +532,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "x['bias'] = 1\n",
+    "data['bias'] = 1\n",
     "other += ['bias']\n",
     "\n",
     "x = data[categorical + numeric + other]\n",
@@ -846,4 +846,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 4
-}
\ No newline at end of file
+}