diff --git a/ThinkPythonNotebooks.zip b/ThinkPythonNotebooks.zip
index fb26e2f..f5c7866 100644
Binary files a/ThinkPythonNotebooks.zip and b/ThinkPythonNotebooks.zip differ
diff --git a/chapters/chap00.ipynb b/chapters/chap00.ipynb
index b42d9c0..e7c283c 100644
--- a/chapters/chap00.ipynb
+++ b/chapters/chap00.ipynb
@@ -50,7 +50,7 @@
     "\n",
     "Writing this book, I tried to be careful with the vocabulary.\n",
     "I define each term when it first appears.\n",
-    "And there is a glossary that the end of each chapter that reviews the terms that were introduced.\n",
+    "And there is a glossary at the end of each chapter that reviews the terms that were introduced.\n",
     "\n",
     "I also tried to be concise.\n",
     "The less mental effort it takes to read the book, the more capacity you will have for programming.\n",
diff --git a/chapters/chap10.ipynb b/chapters/chap10.ipynb
index 5c12688..742da86 100644
--- a/chapters/chap10.ipynb
+++ b/chapters/chap10.ipynb
@@ -1364,7 +1364,7 @@
    "id": "170f1deb",
    "metadata": {},
    "source": [
-    "### Ask an assistant\n",
+    "### Ask a virtual assistant\n",
     "\n",
     "In this chapter, I said the keys in a dictionary have to be hashable and I gave a short explanation. If you would like more details, ask a virtual assistant, \"Why do keys in Python dictionaries have to be hashable?\"\n",
     "\n",
@@ -1559,7 +1559,7 @@
    "source": [
     "### Exercise\n",
     "\n",
-    "Write function called `find_repeats` that takes a dictionary that maps from each key to a counter, like the result from `value_counts`.\n",
+    "Write a function called `find_repeats` that takes a dictionary that maps from each key to a counter, like the result from `value_counts`.\n",
     "It should loop through the dictionary and return a list of keys that have counts greater than `1`.\n",
     "You can use the following outline to get started."
    ]
diff --git a/chapters/chap12.ipynb b/chapters/chap12.ipynb
index f3f7b19..f2d5d23 100644
--- a/chapters/chap12.ipynb
+++ b/chapters/chap12.ipynb
@@ -80,7 +80,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 2,
    "id": "4cd1c980",
    "metadata": {
     "tags": []
@@ -103,7 +103,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 3,
    "id": "52ebfe94",
    "metadata": {
     "tags": []
@@ -116,7 +116,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 4,
    "id": "49cfc352",
    "metadata": {
     "tags": []
@@ -142,7 +142,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 5,
    "id": "44e53ce6",
    "metadata": {},
    "outputs": [],
@@ -152,7 +152,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 6,
    "id": "50d1fafa",
    "metadata": {
     "tags": []
@@ -173,7 +173,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 7,
    "id": "16d24028",
    "metadata": {},
    "outputs": [],
@@ -201,7 +201,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 88,
+   "execution_count": 8,
    "id": "1668e6bd",
    "metadata": {},
    "outputs": [],
@@ -241,7 +241,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 9,
    "id": "ed5f0a43",
    "metadata": {},
    "outputs": [],
@@ -261,7 +261,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": 10,
    "id": "a9df2aeb",
    "metadata": {},
    "outputs": [],
@@ -283,7 +283,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": 11,
    "id": "b138b123",
    "metadata": {},
    "outputs": [],
@@ -305,7 +305,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": 12,
    "id": "fe65df44",
    "metadata": {},
    "outputs": [],
@@ -324,7 +324,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": 13,
    "id": "b47a87cf",
    "metadata": {},
    "outputs": [],
@@ -347,7 +347,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 16,
+   "execution_count": 14,
    "id": "348949be",
    "metadata": {},
    "outputs": [],
@@ -366,7 +366,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 17,
+   "execution_count": 15,
    "id": "06121901",
    "metadata": {},
    "outputs": [],
@@ -385,7 +385,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 18,
+   "execution_count": 16,
    "id": "881ed9f8",
    "metadata": {},
    "outputs": [],
@@ -403,7 +403,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 19,
+   "execution_count": 17,
    "id": "ab5d2fed",
    "metadata": {},
    "outputs": [],
@@ -421,7 +421,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 20,
+   "execution_count": 18,
    "id": "2fdfb936",
    "metadata": {},
    "outputs": [],
@@ -446,7 +446,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 21,
+   "execution_count": 19,
    "id": "3104d191",
    "metadata": {},
    "outputs": [],
@@ -474,7 +474,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 22,
+   "execution_count": 20,
    "id": "4fba7d1c",
    "metadata": {},
    "outputs": [],
@@ -502,7 +502,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 23,
+   "execution_count": 21,
    "id": "4be34c95",
    "metadata": {},
    "outputs": [],
@@ -520,12 +520,12 @@
     "\n",
     "* `key=second_element` means the items will be sorted according to the frequencies of the words.\n",
     "\n",
-    "* `reverse=True` means they items will be sorted in reverse order, with the most frequent words first."
+    "* `reverse=True` means the items will be sorted in reverse order, with the most frequent words first."
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 24,
+   "execution_count": 22,
    "id": "8efe7c4c",
    "metadata": {},
    "outputs": [],
@@ -543,7 +543,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 25,
+   "execution_count": 23,
    "id": "79c17341",
    "metadata": {},
    "outputs": [],
@@ -574,7 +574,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 26,
+   "execution_count": 24,
    "id": "838bcb4f",
    "metadata": {},
    "outputs": [],
@@ -593,7 +593,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 27,
+   "execution_count": 25,
    "id": "90c45e7e",
    "metadata": {},
    "outputs": [],
@@ -617,7 +617,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 28,
+   "execution_count": 26,
    "id": "e106be95",
    "metadata": {},
    "outputs": [],
@@ -635,7 +635,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 29,
+   "execution_count": 27,
    "id": "8101a510",
    "metadata": {},
    "outputs": [],
@@ -655,7 +655,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 30,
+   "execution_count": 28,
    "id": "c046117b",
    "metadata": {
     "tags": []
@@ -697,7 +697,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 31,
+   "execution_count": 29,
    "id": "edd8ff1c",
    "metadata": {
     "tags": []
@@ -717,7 +717,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 32,
+   "execution_count": 30,
    "id": "67ef3e08",
    "metadata": {},
    "outputs": [],
@@ -730,12 +730,12 @@
    "id": "22becbab",
    "metadata": {},
    "source": [
-    "The we'll store the words as keys in a dictionary so we can use the `in` operator to check quickly whether a word is valid."
+    "Then we'll store the words as keys in a dictionary so we can use the `in` operator to check quickly whether a word is valid."
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 33,
+   "execution_count": 31,
    "id": "471d58e9",
    "metadata": {},
    "outputs": [],
@@ -755,7 +755,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 34,
+   "execution_count": 32,
    "id": "4d4c3538",
    "metadata": {},
    "outputs": [],
@@ -778,7 +778,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 35,
+   "execution_count": 33,
    "id": "8b42e014",
    "metadata": {},
    "outputs": [],
@@ -796,7 +796,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 36,
+   "execution_count": 34,
    "id": "f48be152",
    "metadata": {},
    "outputs": [],
@@ -817,7 +817,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 37,
+   "execution_count": 35,
    "id": "5716f967",
    "metadata": {},
    "outputs": [],
@@ -838,7 +838,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 38,
+   "execution_count": 36,
    "id": "b37219f5",
    "metadata": {},
    "outputs": [],
@@ -880,7 +880,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 39,
+   "execution_count": 37,
    "id": "75b548a9",
    "metadata": {},
    "outputs": [],
@@ -890,7 +890,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 40,
+   "execution_count": 38,
    "id": "2bfa31ae",
    "metadata": {
     "tags": []
@@ -913,7 +913,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 41,
+   "execution_count": 39,
    "id": "6f5d5c1c",
    "metadata": {},
    "outputs": [],
@@ -932,7 +932,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 42,
+   "execution_count": 40,
    "id": "1445068b",
    "metadata": {},
    "outputs": [],
@@ -952,7 +952,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 43,
+   "execution_count": 41,
    "id": "4fc47ecd",
    "metadata": {
     "tags": []
@@ -974,7 +974,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 44,
+   "execution_count": 42,
    "id": "91ae9d4c",
    "metadata": {},
    "outputs": [],
@@ -993,7 +993,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 45,
+   "execution_count": 43,
    "id": "8bf595c1",
    "metadata": {},
    "outputs": [],
@@ -1016,7 +1016,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 46,
+   "execution_count": 44,
    "id": "22953b65",
    "metadata": {},
    "outputs": [],
@@ -1034,7 +1034,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 47,
+   "execution_count": 45,
    "id": "1c7cdf4d",
    "metadata": {},
    "outputs": [],
@@ -1052,7 +1052,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 48,
+   "execution_count": 46,
    "id": "a7a3aa42",
    "metadata": {},
    "outputs": [],
@@ -1071,7 +1071,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 49,
+   "execution_count": 47,
    "id": "c4286fb3",
    "metadata": {},
    "outputs": [],
@@ -1111,7 +1111,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 50,
+   "execution_count": 48,
    "id": "d8ee02f6",
    "metadata": {},
    "outputs": [],
@@ -1131,7 +1131,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 51,
+   "execution_count": 49,
    "id": "bfdb1de1",
    "metadata": {},
    "outputs": [],
@@ -1158,7 +1158,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 52,
+   "execution_count": 50,
    "id": "2e73df79",
    "metadata": {},
    "outputs": [],
@@ -1176,7 +1176,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 53,
+   "execution_count": 51,
    "id": "495ad429",
    "metadata": {},
    "outputs": [],
@@ -1206,7 +1206,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 54,
+   "execution_count": 52,
    "id": "c1224061",
    "metadata": {},
    "outputs": [],
@@ -1228,7 +1228,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 55,
+   "execution_count": 53,
    "id": "4296485a",
    "metadata": {},
    "outputs": [],
@@ -1247,7 +1247,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 56,
+   "execution_count": 54,
    "id": "e03fd803",
    "metadata": {
     "tags": []
@@ -1259,7 +1259,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 57,
+   "execution_count": 55,
    "id": "f6ee1840",
    "metadata": {},
    "outputs": [],
@@ -1282,7 +1282,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 58,
+   "execution_count": 56,
    "id": "d6c65d79",
    "metadata": {},
    "outputs": [],
@@ -1312,7 +1312,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 59,
+   "execution_count": 57,
    "id": "3171d592",
    "metadata": {},
    "outputs": [],
@@ -1335,7 +1335,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 60,
+   "execution_count": 58,
    "id": "3321e6a4",
    "metadata": {},
    "outputs": [],
@@ -1353,7 +1353,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 61,
+   "execution_count": 59,
    "id": "e4e55c71",
    "metadata": {},
    "outputs": [],
@@ -1372,7 +1372,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 62,
+   "execution_count": 60,
    "id": "f25dcb5e",
    "metadata": {},
    "outputs": [],
@@ -1391,7 +1391,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 63,
+   "execution_count": 61,
    "id": "990354a0",
    "metadata": {},
    "outputs": [],
@@ -1413,7 +1413,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 64,
+   "execution_count": 62,
    "id": "b9371452",
    "metadata": {},
    "outputs": [],
@@ -1441,7 +1441,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 65,
+   "execution_count": 63,
    "id": "8c3f45c2",
    "metadata": {},
    "outputs": [],
@@ -1464,7 +1464,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 66,
+   "execution_count": 64,
    "id": "641990a3",
    "metadata": {},
    "outputs": [],
@@ -1487,7 +1487,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 67,
+   "execution_count": 65,
    "id": "9322a49a",
    "metadata": {},
    "outputs": [],
@@ -1509,7 +1509,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 68,
+   "execution_count": 66,
    "id": "45a60c52",
    "metadata": {},
    "outputs": [],
@@ -1533,7 +1533,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 69,
+   "execution_count": 67,
    "id": "3e86102c",
    "metadata": {
     "tags": []
@@ -1553,7 +1553,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 70,
+   "execution_count": 68,
    "id": "e49d52f7",
    "metadata": {},
    "outputs": [],
@@ -1590,7 +1590,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 71,
+   "execution_count": 69,
    "id": "15108884",
    "metadata": {},
    "outputs": [],
@@ -1602,7 +1602,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 72,
+   "execution_count": 70,
    "id": "747a41be",
    "metadata": {
     "tags": []
@@ -1626,7 +1626,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 73,
+   "execution_count": 71,
    "id": "5a4682dc",
    "metadata": {},
    "outputs": [],
@@ -1647,7 +1647,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 74,
+   "execution_count": 72,
    "id": "36ee0f76",
    "metadata": {},
    "outputs": [],
@@ -1782,7 +1782,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 73,
    "id": "05752b6d",
    "metadata": {
     "tags": []
@@ -1807,7 +1807,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 75,
+   "execution_count": 74,
    "id": "a4365ac0",
    "metadata": {},
    "outputs": [],
@@ -1827,7 +1827,7 @@
    "metadata": {},
    "source": [
     "Dictionaries provide a method called `setdefault` that we can use to do the same thing more concisely.\n",
-    "Ask a virtual assistant how it works, or copy `add_word` into a virtual assistant and ask \"Can you rewrite this using `setdefault`?\"\n",
+    "Ask a virtual assistant how it works, or copy `add_bigram` into a virtual assistant and ask \"Can you rewrite this using `setdefault`?\"\n",
     "\n",
     "In this chapter we implemented Markov chain text analysis and generation.\n",
     "If you are curious, you can ask a virtual assistant for more information on the topic.\n",
@@ -1850,7 +1850,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 76,
+   "execution_count": 75,
    "id": "f38a61ff",
    "metadata": {},
    "outputs": [],
@@ -1860,7 +1860,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 77,
+   "execution_count": 76,
    "id": "d047e546",
    "metadata": {},
    "outputs": [],
@@ -1880,7 +1880,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 78,
+   "execution_count": 77,
    "id": "6b8932ee",
    "metadata": {
     "tags": []
@@ -1908,7 +1908,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 79,
+   "execution_count": 78,
    "id": "44c3f0d8",
    "metadata": {
     "tags": []
@@ -1932,7 +1932,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 80,
+   "execution_count": 79,
    "id": "3fcf85f4",
    "metadata": {},
    "outputs": [],
@@ -1950,7 +1950,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 81,
+   "execution_count": 80,
    "id": "d9e554e3",
    "metadata": {},
    "outputs": [],
@@ -1975,7 +1975,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 82,
+   "execution_count": 81,
    "id": "8c2ee21c",
    "metadata": {
     "tags": []
@@ -2003,7 +2003,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 83,
+   "execution_count": 82,
    "id": "b13384e3",
    "metadata": {
     "tags": []
@@ -2023,7 +2023,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 84,
+   "execution_count": 83,
    "id": "62c2177f",
    "metadata": {},
    "outputs": [],
@@ -2057,7 +2057,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 85,
+   "execution_count": 84,
    "id": "64e11f26",
    "metadata": {
     "tags": []
@@ -2081,7 +2081,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 86,
+   "execution_count": 85,
    "id": "fe2d93fa",
    "metadata": {},
    "outputs": [],
@@ -2109,7 +2109,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 89,
+   "execution_count": 86,
    "id": "22210a5c",
    "metadata": {},
    "outputs": [],
diff --git a/chapters/chap14.ipynb b/chapters/chap14.ipynb
index 2236a58..f0f9998 100644
--- a/chapters/chap14.ipynb
+++ b/chapters/chap14.ipynb
@@ -907,7 +907,7 @@
     "    \n",
     "    carry, time.second = divmod(time.second, 60)\n",
     "    carry, time.minute = divmod(time.minute + carry, 60)\n",
-    "    carry, time.hour = divmod(time.hour + carry, 60)"
+    "    carry, time.hour = divmod(time.hour + carry, 24)"
    ]
   },
   {
diff --git a/chapters/chap15.ipynb b/chapters/chap15.ipynb
index 39bebc0..f7dfa60 100644
--- a/chapters/chap15.ipynb
+++ b/chapters/chap15.ipynb
@@ -373,7 +373,7 @@
    "id": "e6a18c76",
    "metadata": {},
    "source": [
-    "Now that we have `Time.from_seconds`, we can use it to write `add_time` as a method.\n",
+    "Now that we have `Time.int_to_time`, we can use it to write `add_time` as a method.\n",
     "Here's the function from the previous chapter."
    ]
   },
@@ -409,7 +409,7 @@
     "\n",
     "    def add_time(self, hours, minutes, seconds):\n",
     "        duration = make_time(hours, minutes, seconds)\n",
-    "        seconds = time_to_int(self) + time_to_int(duration)\n",
+    "        seconds = Time.time_to_int(self) + Time.time_to_int(duration)\n",
     "        return Time.int_to_time(seconds)"
    ]
   },
@@ -431,7 +431,7 @@
    "outputs": [],
    "source": [
     "end = start.add_time(1, 32, 0)\n",
-    "print_time(end)"
+    "end.print_time()"
    ]
   },
   {
@@ -604,7 +604,7 @@
    "id": "e01e9673",
    "metadata": {},
    "source": [
-    "## The __init__ method\n",
+    "## The init method\n",
     "\n",
     "The most special of the special methods is `__init__`, so-called because it initializes the attributes of a new object.\n",
     "An `__init__` method for the `Time` class might look like this:"
@@ -836,7 +836,7 @@
     "\n",
     "    def is_after(self, other):\n",
     "        assert self.is_valid(), 'self is not a valid Time'\n",
-    "        assert other.is_valid(), 'self is not a valid Time'\n",
+    "        assert other.is_valid(), 'other is not a valid Time'\n",
     "        return self.time_to_int() > other.time_to_int()"
    ]
   },
@@ -924,7 +924,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 36,
    "id": "3115ea33",
    "metadata": {
     "tags": []
@@ -960,7 +960,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 36,
+   "execution_count": 37,
    "id": "133d7679",
    "metadata": {},
    "outputs": [],
@@ -992,7 +992,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 37,
+   "execution_count": 38,
    "id": "3c9f3777-4869-481e-9f4e-4223d6028913",
    "metadata": {},
    "outputs": [],
@@ -1012,7 +1012,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 38,
+   "execution_count": 39,
    "id": "fd4b2521-aa71-45da-97eb-ce62ce2714ad",
    "metadata": {
     "tags": []
@@ -1025,7 +1025,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 39,
+   "execution_count": 40,
    "id": "ee3f1294-cad1-406b-a574-045ad2b84294",
    "metadata": {
     "tags": []
@@ -1038,7 +1038,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 40,
+   "execution_count": 41,
    "id": "ac093f7b-83cf-4488-8842-5c71bcfa35ec",
    "metadata": {
     "tags": []
@@ -1050,7 +1050,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 41,
+   "execution_count": 42,
    "id": "7e7cb5e1-631f-4b1e-874f-eb16d4792625",
    "metadata": {
     "tags": []
diff --git a/chapters/chap16.ipynb b/chapters/chap16.ipynb
index 57f3d41..eb84e1c 100644
--- a/chapters/chap16.ipynb
+++ b/chapters/chap16.ipynb
@@ -234,7 +234,7 @@
    "id": "a7a635ee",
    "metadata": {},
    "source": [
-    "In the same way that the built in function `sort` modifies a list, and the `sorted` function creates a new list, now we have a `translate` method that modifies a `Point` and a `translated` method that creates a new one.\n",
+    "In the same way that the `sort` method modifies a list and the `sorted` function creates a new list, now we have a `translate` method that modifies a `Point` and a `translated` method that creates a new one.\n",
     "\n",
     "Here's an example:"
    ]
diff --git a/chapters/chap18.ipynb b/chapters/chap18.ipynb
index 41d5fc1..3027822 100644
--- a/chapters/chap18.ipynb
+++ b/chapters/chap18.ipynb
@@ -1661,7 +1661,7 @@
    "id": "07be77f3",
    "metadata": {},
    "source": [
-    "In this example, the value of `kwargs` is printed, but otherwise is has no effect.\n",
+    "In this example, the value of `kwargs` is printed, but otherwise it has no effect.\n",
     "\n",
     "But the `**` operator can also be used in an argument list to unpack a dictionary.\n",
     "For example, here's a version of `mean` that packs any keyword arguments it gets and then unpacks them as keyword arguments for `sum`."