diff --git a/17_foundations.ipynb b/17_foundations.ipynb
index 63252bd..20132be 100644
--- a/17_foundations.ipynb
+++ b/17_foundations.ipynb
@@ -2198,7 +2198,7 @@
     "    \n",
     "    def bwd(self, out, inp):\n",
     "        inp.g = out.g @ self.w.t()\n",
-    "        self.w.g = self.inp.t() @ self.out.g\n",
+    "        self.w.g = inp.t() @ self.out.g\n",
     "        self.b.g = out.g.sum(0)"
    ]
   },