diff --git a/100-pandas-puzzles.ipynb b/100-pandas-puzzles.ipynb
index bcafc2be8..0a6877830 100644
--- a/100-pandas-puzzles.ipynb
+++ b/100-pandas-puzzles.ipynb
@@ -41,12 +41,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {
     "collapsed": true
    },
    "outputs": [],
-   "source": []
+   "source": [
+    "import pandas as pd"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -57,12 +59,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 4,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "2.2.2\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(pd.__version__)"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -73,12 +85,94 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 5,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "/usr/local/python/3.10.13/lib/python3.10/site-packages/_distutils_hack/__init__.py:33: UserWarning: Setuptools is replacing distutils.\n",
+      "  warnings.warn(\"Setuptools is replacing distutils.\")\n"
+     ]
+    },
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "\n",
+      "INSTALLED VERSIONS\n",
+      "------------------\n",
+      "commit                : d9cdd2ee5a58015ef6f4d15c7226110c9aab8140\n",
+      "python                : 3.10.13.final.0\n",
+      "python-bits           : 64\n",
+      "OS                    : Linux\n",
+      "OS-release            : 6.2.0-1019-azure\n",
+      "Version               : #19~22.04.1-Ubuntu SMP Wed Jan 10 22:57:03 UTC 2024\n",
+      "machine               : x86_64\n",
+      "processor             : x86_64\n",
+      "byteorder             : little\n",
+      "LC_ALL                : None\n",
+      "LANG                  : C.UTF-8\n",
+      "LOCALE                : en_US.UTF-8\n",
+      "\n",
+      "pandas                : 2.2.2\n",
+      "numpy                 : 1.26.4\n",
+      "pytz                  : 2024.1\n",
+      "dateutil              : 2.9.0.post0\n",
+      "setuptools            : 68.2.2\n",
+      "pip                   : 24.0\n",
+      "Cython                : None\n",
+      "pytest                : None\n",
+      "hypothesis            : None\n",
+      "sphinx                : None\n",
+      "blosc                 : None\n",
+      "feather               : None\n",
+      "xlsxwriter            : None\n",
+      "lxml.etree            : None\n",
+      "html5lib              : None\n",
+      "pymysql               : None\n",
+      "psycopg2              : None\n",
+      "jinja2                : 3.1.3\n",
+      "IPython               : 8.24.0\n",
+      "pandas_datareader     : None\n",
+      "adbc-driver-postgresql: None\n",
+      "adbc-driver-sqlite    : None\n",
+      "bs4                   : 4.12.3\n",
+      "bottleneck            : None\n",
+      "dataframe-api-compat  : None\n",
+      "fastparquet           : None\n",
+      "fsspec                : 2024.3.1\n",
+      "gcsfs                 : None\n",
+      "matplotlib            : 3.8.4\n",
+      "numba                 : None\n",
+      "numexpr               : None\n",
+      "odfpy                 : None\n",
+      "openpyxl              : None\n",
+      "pandas_gbq            : None\n",
+      "pyarrow               : None\n",
+      "pyreadstat            : None\n",
+      "python-calamine       : None\n",
+      "pyxlsb                : None\n",
+      "s3fs                  : None\n",
+      "scipy                 : 1.13.0\n",
+      "sqlalchemy            : None\n",
+      "tables                : None\n",
+      "tabulate              : None\n",
+      "xarray                : None\n",
+      "xlrd                  : None\n",
+      "zstandard             : None\n",
+      "tzdata                : 2024.1\n",
+      "qtpy                  : None\n",
+      "pyqt5                 : None\n"
+     ]
+    }
+   ],
+   "source": [
+    "pd.show_versions()"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -112,7 +206,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 7,
    "metadata": {
     "collapsed": true
    },
@@ -127,7 +221,7 @@
     "\n",
     "labels = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']\n",
     "\n",
-    "df = # (complete this line of code)"
+    "df = pd.DataFrame(data = data,index=labels)"
    ]
   },
   {
@@ -139,12 +233,83 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 10,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>count</th>\n",
+       "      <th>mean</th>\n",
+       "      <th>std</th>\n",
+       "      <th>min</th>\n",
+       "      <th>25%</th>\n",
+       "      <th>50%</th>\n",
+       "      <th>75%</th>\n",
+       "      <th>max</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>age</th>\n",
+       "      <td>8.0</td>\n",
+       "      <td>3.4375</td>\n",
+       "      <td>2.007797</td>\n",
+       "      <td>0.5</td>\n",
+       "      <td>2.375</td>\n",
+       "      <td>3.0</td>\n",
+       "      <td>4.625</td>\n",
+       "      <td>7.0</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>visits</th>\n",
+       "      <td>10.0</td>\n",
+       "      <td>1.9000</td>\n",
+       "      <td>0.875595</td>\n",
+       "      <td>1.0</td>\n",
+       "      <td>1.000</td>\n",
+       "      <td>2.0</td>\n",
+       "      <td>2.750</td>\n",
+       "      <td>3.0</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "        count    mean       std  min    25%  50%    75%  max\n",
+       "age       8.0  3.4375  2.007797  0.5  2.375  3.0  4.625  7.0\n",
+       "visits   10.0  1.9000  0.875595  1.0  1.000  2.0  2.750  3.0"
+      ]
+     },
+     "execution_count": 10,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df.describe().T"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -155,12 +320,79 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 11,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "      <th>visits</th>\n",
+       "      <th>priority</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>a</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.5</td>\n",
+       "      <td>1</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>b</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>3.0</td>\n",
+       "      <td>3</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>c</th>\n",
+       "      <td>snake</td>\n",
+       "      <td>0.5</td>\n",
+       "      <td>2</td>\n",
+       "      <td>no</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "  animal  age  visits priority\n",
+       "a    cat  2.5       1      yes\n",
+       "b    cat  3.0       3      yes\n",
+       "c  snake  0.5       2       no"
+      ]
+     },
+     "execution_count": 11,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df.head(3)"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -171,12 +403,113 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 12,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>a</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.5</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>b</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>3.0</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>c</th>\n",
+       "      <td>snake</td>\n",
+       "      <td>0.5</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>d</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>NaN</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>e</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>5.0</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>f</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.0</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>g</th>\n",
+       "      <td>snake</td>\n",
+       "      <td>4.5</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>h</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>NaN</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>i</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>7.0</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>j</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>3.0</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "  animal  age\n",
+       "a    cat  2.5\n",
+       "b    cat  3.0\n",
+       "c  snake  0.5\n",
+       "d    dog  NaN\n",
+       "e    dog  5.0\n",
+       "f    cat  2.0\n",
+       "g  snake  4.5\n",
+       "h    cat  NaN\n",
+       "i    dog  7.0\n",
+       "j    dog  3.0"
+      ]
+     },
+     "execution_count": 12,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df[['animal','age']]"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -187,12 +520,71 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 17,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>d</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>NaN</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>e</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>5.0</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>i</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>7.0</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "  animal  age\n",
+       "d    dog  NaN\n",
+       "e    dog  5.0\n",
+       "i    dog  7.0"
+      ]
+     },
+     "execution_count": 17,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df[['animal','age']].iloc[[3,4,8]]"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -203,12 +595,57 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 21,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "      <th>visits</th>\n",
+       "      <th>priority</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "Empty DataFrame\n",
+       "Columns: [animal, age, visits, priority]\n",
+       "Index: []"
+      ]
+     },
+     "execution_count": 21,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df[df.visits > 3]"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -219,12 +656,71 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 22,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "      <th>visits</th>\n",
+       "      <th>priority</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>d</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>NaN</td>\n",
+       "      <td>3</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>h</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>NaN</td>\n",
+       "      <td>1</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "  animal  age  visits priority\n",
+       "d    dog  NaN       3      yes\n",
+       "h    cat  NaN       1      yes"
+      ]
+     },
+     "execution_count": 22,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df[df.age.isnull()]"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -235,12 +731,71 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 27,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "      <th>visits</th>\n",
+       "      <th>priority</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>a</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.5</td>\n",
+       "      <td>1</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>f</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.0</td>\n",
+       "      <td>3</td>\n",
+       "      <td>no</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "  animal  age  visits priority\n",
+       "a    cat  2.5       1      yes\n",
+       "f    cat  2.0       3       no"
+      ]
+     },
+     "execution_count": 27,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df[(df['animal'] == \"cat\")& (df['age']<3)]"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -251,12 +806,87 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 28,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<div>\n",
+       "<style scoped>\n",
+       "    .dataframe tbody tr th:only-of-type {\n",
+       "        vertical-align: middle;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe tbody tr th {\n",
+       "        vertical-align: top;\n",
+       "    }\n",
+       "\n",
+       "    .dataframe thead th {\n",
+       "        text-align: right;\n",
+       "    }\n",
+       "</style>\n",
+       "<table border=\"1\" class=\"dataframe\">\n",
+       "  <thead>\n",
+       "    <tr style=\"text-align: right;\">\n",
+       "      <th></th>\n",
+       "      <th>animal</th>\n",
+       "      <th>age</th>\n",
+       "      <th>visits</th>\n",
+       "      <th>priority</th>\n",
+       "    </tr>\n",
+       "  </thead>\n",
+       "  <tbody>\n",
+       "    <tr>\n",
+       "      <th>a</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.5</td>\n",
+       "      <td>1</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>b</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>3.0</td>\n",
+       "      <td>3</td>\n",
+       "      <td>yes</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>f</th>\n",
+       "      <td>cat</td>\n",
+       "      <td>2.0</td>\n",
+       "      <td>3</td>\n",
+       "      <td>no</td>\n",
+       "    </tr>\n",
+       "    <tr>\n",
+       "      <th>j</th>\n",
+       "      <td>dog</td>\n",
+       "      <td>3.0</td>\n",
+       "      <td>1</td>\n",
+       "      <td>no</td>\n",
+       "    </tr>\n",
+       "  </tbody>\n",
+       "</table>\n",
+       "</div>"
+      ],
+      "text/plain": [
+       "  animal  age  visits priority\n",
+       "a    cat  2.5       1      yes\n",
+       "b    cat  3.0       3      yes\n",
+       "f    cat  2.0       3       no\n",
+       "j    dog  3.0       1       no"
+      ]
+     },
+     "execution_count": 28,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df[(df['age']>=2) & (df['age']<=  4)]"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -267,12 +897,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 41,
    "metadata": {
     "collapsed": true
    },
    "outputs": [],
-   "source": []
+   "source": [
+    "df.loc['f','age'] = 1.5"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -283,12 +915,25 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 42,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "19"
+      ]
+     },
+     "execution_count": 42,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df.visits.sum()"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -299,12 +944,25 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 43,
    "metadata": {
     "collapsed": true
    },
-   "outputs": [],
-   "source": []
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "3.375"
+      ]
+     },
+     "execution_count": 43,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "df.age.mean()"
+   ]
   },
   {
    "cell_type": "markdown",
@@ -320,7 +978,9 @@
     "collapsed": true
    },
    "outputs": [],
-   "source": []
+   "source": [
+    "df."
+   ]
   },
   {
    "cell_type": "markdown",
@@ -1452,7 +2112,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -1466,7 +2126,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.4"
+   "version": "3.10.13"
   }
  },
  "nbformat": 4,