diff --git a/brisk_python.Rmd b/brisk_python.Rmd
index 6851e55c..0b88e091 100644
--- a/brisk_python.Rmd
+++ b/brisk_python.Rmd
@@ -72,6 +72,13 @@ a + b
 a * b
 ```
 
+By default, jupyter notebook cells will only print the results of the last line of code when it is not assigned to a variable. To print the results of previous lines of codes in the cell as well, the function print() can be used:
+
+```{python}
+print(a + b)
+a * b
+```
+
 Dividing an int by an int also gives a float:
 
 ```{python}
@@ -107,7 +114,6 @@ The `%` operator on numbers gives you the remainder of integer division
 5.0 % 2.0
 ```
 
-(true-and-false)=
 
 ## True and False
 
@@ -186,7 +192,6 @@ different from MATLAB, which uses `~=`:
 a != 1
 ```
 
-(comparison-operators)=
 
 ## Comparison operators
 
@@ -269,7 +274,7 @@ print('not True:', not True)
 print('not False:', not False)
 ```
 
-In fact, the logical operators will first force their arguments to be True or False before they give their answer.  So, in the case of `and` or `or`, they force force their left and right arguents to be `bool` values, before they calculate the answer.  So, in fact, you can use things other than exact True and False on either side of the `and` or `or`, as long as applying `bool(value)` to the thing to the left and right will produce a True or False value.  See {doc}`truthiness` for more detail.
+In fact, the logical operators will first force their arguments to be True or False before they give their answer.  So, in the case of `and` or `or`, they force their left and right arguents to be `bool` values, before they calculate the answer.  So, in fact, you can use things other than exact True and False on either side of the `and` or `or`, as long as applying `bool(value)` to the thing to the left and right will produce a True or False value.  See {doc}`truthiness` for more detail.
 
 ## “If” statements, blocks and indention
 
@@ -689,7 +694,6 @@ you a reversed copy of the list:
 my_list[::-1]
 ```
 
-(tuples)=
 
 ## Tuples
 
@@ -869,7 +873,7 @@ characters removed from the beginning and end of the string:
 ```{python}
 # A string with a newline character at the end
 my_string = ' a string\n'
-my_string
+print(my_string)
 my_string.strip()
 ```
 
@@ -1064,7 +1068,7 @@ software = {}
 ```
 
 Here we insert a new key / value mapping into the dictionary. The key is a
-string — `'Python'` — and the corresponding value is an integer 50:
+string — `'Python'` — and the corresponding value is an integer 100:
 
 ```{python}
 software['Python'] = 100
diff --git a/choosing_editor.md b/choosing_editor.md
index 6ab8a06e..baf5e1fc 100644
--- a/choosing_editor.md
+++ b/choosing_editor.md
@@ -76,6 +76,7 @@ to PyCharm users).
 * [Sublime text](https://www.sublimetext.com)
 * [Emacs](https://emacs.org)
 * [Spyder](https://www.spyder-ide.org)
+* [GitHub Codespaces](https://github.com/features/codespaces)
 
 ## Some version of Visual Studio Code
 
diff --git a/the_software.md b/the_software.md
index 2ad88e30..f4f616bb 100644
--- a/the_software.md
+++ b/the_software.md
@@ -40,7 +40,7 @@ post](http://asterisk.dynevor.org/python-matlab.html).
 
 ## The Jupyter Notebook
 
-We will soon here more about the Jupyter Notebook.  It is a particularly
+We will soon hear more about the Jupyter Notebook.  It is a particularly
 easy interface to run Python code, and display the results.
 
 The Notebook has two parts.  The first is the web application, that you
diff --git a/what_is_an_image.Rmd b/what_is_an_image.Rmd
index 14eefa33..13b332c6 100644
--- a/what_is_an_image.Rmd
+++ b/what_is_an_image.Rmd
@@ -79,11 +79,16 @@ import os  # module for interacting with the operating system
 If you want to explore modules or objects, type their name followed by a
 period, and press tab to see what functions or classes are available.
 
-Try this now.  Type  ( followed by a period) then press tab, to see
+Try this now.  Type os (followed by a period) then press tab, to see
 what functions are in the `os` module. Continue typing so you have
-`os.getcwd`, and then type `?` followed by Return. This shows you
+`os.getcwd`, and then type `?` followed by SHIFT + Return. This shows you
 the help for the `os.getcwd` function.
 
+```{python}
+# Cell to follow instructions in the previous parragraph
+os.
+```
+
 For example, here we print out the Python's *working directory*.  It is the
 directory that contains this notebook file.
 
@@ -145,7 +150,7 @@ How do I find out what `type` of object is attached to this variable called
 
 How big is this file in terms of bytes? Can you find out from the
 `contents` variable? (Hint: you want to know the length of
-`contents`).
+`contents`; Hint 2: use function len() ).
 
 ```{python}
 # n_bytes = ?