@@ -158,7 +158,12 @@ isn't exactly like mine but it works just fine it's ok, and you can
 
 ## Lists and tuples
 
-1. When we run the program we get a weird error:
+1.  Look carefully. The `namelist` is written in `()` instead of `[]`,
+    so it's actually a tuple, not a list. Using confusing variable names
+    is of course a bad idea, but you shouldn't be surprised if someone
+    is doing that. Replace the `()` with `[]` and the code will work.
+
+2. When we run the program we get a weird error:
 
         Hello!
         Enter your name: my name
@@ -189,7 +194,7 @@ isn't exactly like mine but it works just fine it's ok, and you can
     Python created a tuple automatically, but that's not what we
     wanted. If we remove the comma, everything works just fine.
 
-2. Again, the code gives us a weird error message.
+3. Again, the code gives us a weird error message.
 
         Enter your name: my name
         Traceback (most recent call last):
 
@@ -111,10 +111,10 @@ Dictionaries have some similarities with lists. For example, both
 lists and dictionaries have a length.
 
 ```python
->>> len(names_and_pets)     # contains two elements
-2
->>> len(favorite_pets)    # contains two key:value pairs
-2
+>>> len(names_and_pets)     # contains three elements
+3
+>>> len(favorite_pets)    # contains three key:value pairs
+3
 >>>
 ```
 
 
@@ -320,15 +320,24 @@ else:
 
 ## Exercises
 
-1. Fix this program.
+1. Fix this program:
+
+    ```python
+    namelist = ('wub_wub', 'RubyPinch', 'go|dfish', 'Nitori')
+    namelist.append('pb122')
+    if 'pb122' in namelist:
+        print("Now I know pb122!")
+    ```
+
+2. Fix this program.
 
     ```python
     print("Hello!")
     name = input("Enter your name: "),
     print("Your name is " + name + ".")
     ```
 
-2. Fix this program.
+3. Fix this program.
 
     ```python
     namelist = ['wub_wub', 'RubyPinch', 'go|dfish', 'Nitori']