diff --git a/Introduction-to-Python b/Introduction-to-Python
new file mode 160000
index 0000000..eda4e59
--- /dev/null
+++ b/Introduction-to-Python
@@ -0,0 +1 @@
+Subproject commit eda4e59af2fe84c073f3b35d84674b6cd9aa7a68
diff --git a/NumPy/1. Data Types.ipynb b/NumPy/1. Data Types.ipynb
index f6feb84..5123b90 100644
--- a/NumPy/1. Data Types.ipynb	
+++ b/NumPy/1. Data Types.ipynb	
@@ -502,10 +502,23 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 11,
    "metadata": {},
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[260]\n"
+     ]
+    }
+   ],
+   "source": [
+    "import numpy as np\n",
+    "arr = np.array([250], dtype=np.int16)\n",
+    "arr.dtype\n",
+    "print(arr + 10)"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -525,10 +538,27 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 15,
    "metadata": {},
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "8000000\n",
+      "2000000\n",
+      "4.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "import numpy as np\n",
+    "arr = np.zeros([1000000], dtype=np.float64)\n",
+    "print(arr.nbytes)\n",
+    "arr2 = np.zeros([1000000], dtype=np.float16)\n",
+    "print(arr2.nbytes)\n",
+    "print(arr.nbytes / arr2.nbytes)"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -550,21 +580,26 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 23,
    "metadata": {},
    "outputs": [
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "The data type of the array is <U7\n",
-      "The updated array is ['Alexand' 'Bob' 'Charlie']\n",
-      "The re-created array is ['Alexandria' 'Bob' 'Charlie']\n",
-      "The data type of the array is <U11\n"
+      "<U7\n",
+      "['Alexandria' 'Bob' 'Charlie']\n"
      ]
     }
    ],
-   "source": []
+   "source": [
+    "import numpy as np\n",
+    "arr = np.array([\"Alice\", \"Bob\", \"Charlie\"])\n",
+    "print(arr.dtype)\n",
+    "arr[0] = \"Alexandria\"\n",
+    "arr = np.array([\"Alexandria\", \"Bob\", \"Charlie\"], dtype='U10')\n",
+    "print(arr)"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -576,7 +611,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "p310env",
+   "display_name": "Python 3",
    "language": "python",
    "name": "python3"
   },