diff --git a/exercise05_1.ipynb b/exercise05_1.ipynb
index 3071a0f59382cdaae57da0faa34b5e85722ac77e..357f4246a71e6cf27950d284659e3f7d78bbb7ba 100644
--- a/exercise05_1.ipynb
+++ b/exercise05_1.ipynb
@@ -77,12 +77,25 @@
    "cell_type": "code",
    "execution_count": 6,
    "metadata": {},
+   "outputs": [],
+   "source": [
+    "answers = {0: 1, 1: 1}\n",
+    "def fib5(n):\n",
+    "    if not n in answers:\n",
+    "        answers[n] = fib5(n-1) + fib5(n-2)\n",
+    "    return answers[n]"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "3.06 s ± 90.7 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)\n"
+      "2.55 s ± 52.9 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)\n"
      ]
     }
    ],
@@ -92,14 +105,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 8,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "62.2 ns ± 1.44 ns per loop (mean ± std. dev. of 7 runs, 10,000,000 loops each)\n"
+      "57.6 ns ± 0.131 ns per loop (mean ± std. dev. of 7 runs, 10,000,000 loops each)\n"
      ]
     }
    ],
@@ -109,14 +122,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": 9,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "4.09 µs ± 193 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)\n"
+      "3.37 µs ± 82.7 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)\n"
      ]
     }
    ],
@@ -126,20 +139,37 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 10,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "2.76 µs ± 74.1 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)\n"
+      "2.2 µs ± 75.1 ns per loop (mean ± std. dev. of 7 runs, 100,000 loops each)\n"
      ]
     }
    ],
    "source": [
     "%timeit fib4(35)"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "103 ns ± 0.943 ns per loop (mean ± std. dev. of 7 runs, 10,000,000 loops each)\n"
+     ]
+    }
+   ],
+   "source": [
+    "%timeit fib5(35)"
+   ]
   }
  ],
  "metadata": {
@@ -158,7 +188,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.8"
+   "version": "3.10.6"
   },
   "orig_nbformat": 4
  },