diff --git a/Notebooks/Chap07/7_2_Backpropagation.ipynb b/Notebooks/Chap07/7_2_Backpropagation.ipynb
index 93c928c..ffc0b80 100644
--- a/Notebooks/Chap07/7_2_Backpropagation.ipynb
+++ b/Notebooks/Chap07/7_2_Backpropagation.ipynb
@@ -4,7 +4,7 @@
   "metadata": {
     "colab": {
       "provenance": [],
-      "authorship_tag": "ABX9TyM8DZv6WppyaQxi8igoKV+X",
+      "authorship_tag": "ABX9TyPOadzPTZy+kvsBZs5D7n5M",
       "include_colab_link": true
     },
     "kernelspec": {
@@ -254,7 +254,7 @@
         "    # REPLACE THIS LINE\n",
         "    all_dl_dbiases[layer] = np.zeros_like(all_biases[layer])\n",
         "\n",
-        "    # TODO Calculate the derivatives of the loss with respect to the weights at layer from all_dl_df[K] and all_h[K] (eq 7.22)\n",
+        "    # TODO Calculate the derivatives of the loss with respect to the weights at layer from all_dl_df[layer] and all_h[layer] (eq 7.22)\n",
         "    # Don't forget to use np.matmul\n",
         "    # REPLACE THIS LINE\n",
         "    all_dl_dweights[layer] = np.zeros_like(all_weights[layer])\n",