diff --git a/1_list_set_dict.ipynb b/1_list_set_dict.ipynb
index 99d1f2e..ca17aae 100644
--- a/1_list_set_dict.ipynb
+++ b/1_list_set_dict.ipynb
@@ -25,54 +25,6 @@
         "## A list is a value that contains multiple values in an ordered sequence."
       ]
     },
-    {
-      "cell_type": "code",
-      "metadata": {
-        "colab_type": "code",
-        "id": "qn4isYwEqQMK",
-        "colab": {}
-      },
-      "source": [
-        "# list of strings\n",
-        "['apple', 'cherry', 'banana', 'Lemon', 'Grape']\n",
-        "# list of mixtures\n",
-        "[1, 'apple', 'cat', 3.1416]\n",
-        "# list inside list\n",
-        "['apple', [1, 2, 3], 'banana']"
-      ],
-      "execution_count": 0,
-      "outputs": []
-    },
-    {
-      "cell_type": "code",
-      "metadata": {
-        "id": "99gRNRrgirez",
-        "colab_type": "code",
-        "colab": {}
-      },
-      "source": [
-        "# assign a list to a variable\n",
-        "fruits = ['apple', 'cherry', 'banana', 'Lemon', 'Grape']\n",
-        "fruits"
-      ],
-      "execution_count": 0,
-      "outputs": []
-    },
-    {
-      "cell_type": "code",
-      "metadata": {
-        "id": "hXWF4nwN5MDq",
-        "colab_type": "code",
-        "colab": {}
-      },
-      "source": [
-        "# create empty list\n",
-        "empty_list = []\n",
-        "empty_list_2 = list()"
-      ],
-      "execution_count": 0,
-      "outputs": []
-    },
     {
       "cell_type": "markdown",
       "metadata": {
@@ -1144,51 +1096,6 @@
       "execution_count": 0,
       "outputs": []
     },
-    {
-      "cell_type": "markdown",
-      "metadata": {
-        "id": "UhTGTkuim2B1",
-        "colab_type": "text"
-      },
-      "source": [
-        "## Zip(list1, list2, ...)\n",
-        "Combine multipe lists to tuples"
-      ]
-    },
-    {
-      "cell_type": "code",
-      "metadata": {
-        "id": "d1QsVyqamya4",
-        "colab_type": "code",
-        "colab": {}
-      },
-      "source": [
-        "states = ['NJ', 'NY', 'PA']\n",
-        "capitals = ['Trenton', 'Albany', 'Harrisburg']\n",
-        "\n",
-        "for s, c in zip(states, capitals):\n",
-        "    print('The capital city of %s state is %s' % (s, c))"
-      ],
-      "execution_count": 0,
-      "outputs": []
-    },
-    {
-      "cell_type": "code",
-      "metadata": {
-        "id": "7XIzCbhrogr3",
-        "colab_type": "code",
-        "colab": {}
-      },
-      "source": [
-        "states = ['NJ', 'NY', 'PA', 'MD']                # 4 values\n",
-        "capitals = ['Trenton', 'Albany', 'Harrisburg']   # 3 values\n",
-        "\n",
-        "for s, c in zip(states, capitals):\n",
-        "    print('The capital city of %s state is %s' % (s, c))"
-      ],
-      "execution_count": 0,
-      "outputs": []
-    },
     {
       "cell_type": "markdown",
       "metadata": {
@@ -1221,9 +1128,8 @@
       "source": [
         "# SETS\n",
         "\n",
-        "Copied from https://www.geeksforgeeks.org/sets-in-python/\n",
-        "\n",
-        "A Set is an unordered collection data type that is iterable, MUTABLE and has NO DUPLICATE elements. Python's set class represents the mathematical notion of a set."
+        "A Set is collection, unordered, iterable, mutable, no duplicate elements. \n",
+        "Think of sets in math."
       ]
     },
     {
@@ -1493,16 +1399,35 @@
         "colab": {}
       },
       "source": [
-        "d1 = {}\n",
+        "# empty dictionary\n",
+        "d1 = {}  # d1 = dict()\n",
+        "\n",
+        "# add key-value pairs to the dictionary\n",
         "d1['a'] = 12\n",
         "d1['b'] = 3\n",
         "d1['c'] = 47\n",
         "d1['d'] = 18\n",
+        "\n",
+        "# show the dictionary\n",
         "d1"
       ],
       "execution_count": 0,
       "outputs": []
     },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "dr-R17LVKgGW",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        "# access value by key\n",
+        "print(d1['c'])"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
     {
       "cell_type": "code",
       "metadata": {
@@ -1559,6 +1484,117 @@
       "execution_count": 0,
       "outputs": []
     },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "FlT-YzvkaVrQ",
+        "colab_type": "text"
+      },
+      "source": [
+        "## Merge two dictionaries\n",
+        "update() method adds items to the dictionary if the key is not in the dictionary. If the key is in the dictionary, it updates the key with the new value."
+      ]
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "XB7hTMsLadrh",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        "nfl_team_list_1 = {\n",
+        "    'Georgia': 'Atlanta Falcons',\n",
+        "    'New York': 'Buffalo Bills',\n",
+        "    'New Jersey': 'New York Giants',\n",
+        "    'Pennsylvania': 'Philadelphia Eagles'\n",
+        "}\n",
+        "nfl_team_list_2 = {\n",
+        "    'Arizona': 'Arizona Cardinals',\n",
+        "    'New York': 'Buffalo Bills',\n",
+        "    'New Jersey': 'New York Jets',\n",
+        "    'Pennsylvania': 'Pittsburgh Steelers',\n",
+        "    'Illinois': 'Chicago Bears'\n",
+        "}"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "mXQ7SbA7I-tR",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        "nfl_team_list_1.update(nfl_team_list_2)\n",
+        "nfl_team_list_1"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "1kPSFdoE9bUz",
+        "colab_type": "text"
+      },
+      "source": [
+        "## Remove items from a dictionary"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "0DP-VkuX9gbb",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        "# pop() removes an item with speficifed key and returns the value\n",
+        "val = d1.pop('c')\n",
+        "print(val)\n",
+        "print(d1)"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "gjiqArH59gfl",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        "# del\n",
+        "car = {\n",
+        "    'brand': 'Ford',\n",
+        "    'model': 'Explorer',\n",
+        "    'year': 2017,\n",
+        "    'price': 20000\n",
+        "}\n",
+        "car"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "W6XHJwqPZnRy",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        "# del keyword delete item by key\n",
+        "del car['price']\n",
+        "print(car)"
+      ],
+      "execution_count": 0,
+      "outputs": []
+    },
     {
       "cell_type": "markdown",
       "metadata": {
@@ -1577,6 +1613,7 @@
         "colab": {}
       },
       "source": [
+        "d1 = {'a': 12, 'b': 3, 'c': 47, 'd': 18}\n",
         "d1"
       ],
       "execution_count": 0,
@@ -1628,7 +1665,7 @@
         "colab_type": "text"
       },
       "source": [
-        "# Data Structure Examples"
+        "# More Examples"
       ]
     },
     {
@@ -1759,7 +1796,13 @@
         "colab": {}
       },
       "source": [
-        ""
+        "list1 = [3, 4, 5, 6, 2, 1, 4, 9, 0, -2, 7]\n",
+        "list2 = [-3, 8, 5, 6, 2, 1, -5, 9, 12, -2, 11]\n",
+        "\n",
+        "def common_list(l1, l2):\n",
+        "    pass # your code here\n",
+        "\n",
+        "print(common_list(list1, list2))\n"
       ],
       "execution_count": 0,
       "outputs": []
@@ -1771,7 +1814,7 @@
         "colab_type": "text"
       },
       "source": [
-        "2. Write a function that takes a list of numbers and makes a new list of only the first and last elements of the given list. "
+        "2. Write a function that takes a list of numbers and returns the minimum and maximum numbers as a tuple. "
       ]
     },
     {
@@ -1782,7 +1825,12 @@
         "colab": {}
       },
       "source": [
-        ""
+        "num_list = [3, 4, 5, 6, 2, 1, 4, 9, 0, -2, 7]\n",
+        "\n",
+        "def min_max(n_list):\n",
+        "    pass # your code here\n",
+        "\n",
+        "print(min_max(num_list))\n"
       ],
       "execution_count": 0,
       "outputs": []
@@ -1811,7 +1859,13 @@
         "colab": {}
       },
       "source": [
-        ""
+        "def fibonacci_numbers(up_to=10):\n",
+        "    # first two fibonacci numbers\n",
+        "    fibs = [0, 1]\n",
+        "    \n",
+        "    pass   # your code here\n",
+        "\n",
+        "print(fibonacci_numbers())"
       ],
       "execution_count": 0,
       "outputs": []
@@ -1834,7 +1888,11 @@
         "colab": {}
       },
       "source": [
-        ""
+        "def reverse_string(str):\n",
+        "\n",
+        "    pass    # your code here\n",
+        "\n",
+        "print(reverse_string('Friday'))"
       ],
       "execution_count": 0,
       "outputs": []
@@ -1857,11 +1915,37 @@
         "colab": {}
       },
       "source": [
-        ""
+        "def reverse_words(str):\n",
+        "\n",
+        "    pass    # your code here\n",
+        "\n",
+        "str1 = 'Tom chases Jerry'\n",
+        "print(reverse_words(str1))"
       ],
       "execution_count": 0,
       "outputs": []
     },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "62OQOTQs0k5K",
+        "colab_type": "text"
+      },
+      "source": [
+        "6. Given a list of stock records, find out the total number of shares for each stock.\n",
+        "\n",
+        "Symbol, Price, Shares <br>\n",
+        "IBM, 142.3, 50 <br>\n",
+        "MSFT, 170.21, 100 <br>\n",
+        "GOOG, 1469.32, 15 <br>\n",
+        "IBM, 142.3, 20 <br>\n",
+        "C, 74.78, 100 <br>\n",
+        "CAT, 133.73, 80 <br>\n",
+        "C, 74.78, 200 <br>\n",
+        "GOOG, 1469.32, 7 <br>\n",
+        "C, 74.78, 80 <br>"
+      ]
+    },
     {
       "cell_type": "code",
       "metadata": {
@@ -1874,6 +1958,40 @@
       ],
       "execution_count": 0,
       "outputs": []
+    },
+    {
+      "cell_type": "markdown",
+      "metadata": {
+        "id": "hi5vnh-p8J1Y",
+        "colab_type": "text"
+      },
+      "source": [
+        "7. Given a list of stock buy/sell records, find out net values for each stock, and the total net value\n",
+        "\n",
+        "Symbol, Price, Shares, Buy/Sell <br>\n",
+        "IBM, 142.3, 50, Buy <br>\n",
+        "MSFT, 170.21, 100, Buy <br>\n",
+        "GOOG, 1469.32, 15, Buy <br>\n",
+        "IBM, 142.3, 20, Sell <br>\n",
+        "C, 74.78, 100, Buy <br>\n",
+        "CAT, 133.73, 80, Buy <br>\n",
+        "C, 74.78, 200, Buy <br>\n",
+        "GOOG, 1469.32, 7, Sell <br>\n",
+        "C, 74.78, 80, Sell <br>"
+      ]
+    },
+    {
+      "cell_type": "code",
+      "metadata": {
+        "id": "IHOG8kbF8ucE",
+        "colab_type": "code",
+        "colab": {}
+      },
+      "source": [
+        ""
+      ],
+      "execution_count": 0,
+      "outputs": []
     }
   ]
 }
\ No newline at end of file