Python Stage 1 - Updated for Y9 2025

• Computing
• Lower Secondary (Key Stage 3)

Python 

Year 9 

Self guided learning slides

KEY OBJECTIVE

To program a computer using the python programming language

PRIMM

We will be using the PRIMM approach when we learn to code

Predict - look at code and guess what it does

Run - run the code and see it work

Investigate - understand what the code is doing

Modify - make changes to existing code

Make - write a program based on what we have seen

Task 1 - PREDICT

What do you think this code will do?

What will the code do?

RUN

run the code

INVESTIGATE and MODIFY

Using the code you have try and:

• make it say a different message
• Make the message print 3 times by calling the procedure multiple times

Guidance on MAKE stage (RED pages)

• These start with a blank template and you need to write the code from scratch.
• You can use the previous code to reference and check code
• DO NOT copy and paste code as this will not help you learn the syntax 
• Look at existing code, switch to the blank and recall it by typing 
• Remember you always have a similar version to look at from the initial RUN stage so you don't get lost

MAKE

Create your own program that will:

• Have a procedure called "computing" that prints the message "I love computing"
• In the main code call that procedure
• Here is a blank coding window

What is Syntax?

• Rules of writing the code
• Breaking the rules means errors

So it is important!

• where spaces are and aren't
• where punctuation marks are like ""
• using colons : correctly
• using indentation

What is debugging?

• You will make mistakes....frequently
• When this happens you will get error messages
• You need to remove the bugs to make it work
• So we call this debugging

Debugging Continued...

Here is an error you might get.

Errors are either on the line it tells you or the one before the line

So if your error message says line 7 look carefully at lines 6 and 7 for the error.

Common errors to look for

• Missing "" or () or : where they are needed
• wrong name for a variable
• indent levels are wrong 

Task 2 - Debugging

In this task, you will need to debug the code using the error messages that create with code provide.

Click here

Variables 

• Computers need to store data for you that the program needs (like health, XP, points)
• These are called VARIABLES
• In python we declare these using a suitable name and then assign them values

LIKE

health = 100

xp = 0

points = 0

All Variables should:

• Have a sensible name
• be lower case
• have no spaces (only one word long)

Task 3 - Variables - Predict

PREDICT

Also - can you spot the variable in this code?

What do you think the code will do?

RUN

run the code

The variable in this code is of course name

but something weird happens when you run it

How good was your prediction?

Nothing happened?

Check over the code carefully

Sometimes you do not get errors as the computer thinks the code is fine

Look at the last line and how the procedure was called

Notice anything that's missing?

INVESTIGATE and MODIFY

Using the code try the following:

• Fix the call for procedure1 to include the ()
• make the program call the other two procedures as well
• Change the name in the printing2 procedure to your name
• (Harder) Add more text after the greeting in printing3 so it will print the following --> "Hello Sally , nice to meet you"

Taking input

We can ask the user for inputs into our programs.

So instead of setting a variable to store "bob" we can ask the user what their name is and store that instead. 

PREDICT

What do you think this code will do when run?

RUN

Run the program

INVESTIGATE AND MODIFY

Try and do the following:

• change the procedure name for printmyname() to printname()
• add two more input questions to the askmestuff() procedure about a favourite hobby and place in the world and store them in suitable variables
• add another print statement to the same procedure to print suitable text using the new stored variables.

MAKE

Create your own program that:

• has a procedure that asks 2 questions and stores them as variables
• calls this procedure from the main code
• results in a sentence being printed, using the stored variables
• Here is a blank coding window

Syntax errors?

Let's test some of those error checking skills

On the next drag and drop which bits of code are correct and which would cause an error?

CORRECT

CAUSE AN ERROR

print = ("Hello")

Print("Yes!")

print("this one)

name = imput("what is your name")

name = input("what is your name")

print("this text")

fav colour = "Green"

age = 10

print("Hello", name)

print("Bye",name")

Commenting our code. What is the importance?

• Comments are like post-it notes on your code
• The computer will ignore them when you write them
• The explain code and help you come back and edit it later 
  
• Look at the first code you saw - where are the comments?

What symbol is used to tell Python you are writing a comment?

1. :
2. ""
3. ()
4. #

What is the process of checking a program for errors by running it and fixing the issues?

1. Error checking
2. De-bugging
3. Error finding
4. Mistake finding

What type of information can be stored in a variable?

1. Only videos
2. Only sounds
3. Only pictures
4. Numbers, text, and other types of data

Adding conditions

We have been taking inputs, storing variables and outputting results to the screen

Now we need to add some conditions.

So we only do things when certain things happen and not all the time

PREDICT

What do you think this code would do?

RUN

Run the code

Comparisons in code

x==10	when x is equal to the value 10
x!=10	when x does not equal 10
x>10	when x is greater than 10
x<10	when x is less than 10
x>=10	when x is greater or equal to 10
x<=10	when x is greater or equal to 10

Investigate and Modify

Change the code here to do the following:

• Change the condition to check if the name is equal to "Bob"
• if it is "Bob" then say "Hey there Bob! I know you!"
• else then print out "Have you seen Bob anywhere?"

MAKE

Make a program that

• Has a procedure called checkfood():
• Ask the user to enter their favourite food and store it as a suitable variable
• Check if their favourite food is "pizza" or not
• If it is then print something positive about it
• If it isn't then say something negative about it
• Call the procedure you made in the main code routine
• Here is a blank to code in

If this, if that

• Sometimes we need to check for more than one thing
• And we need to check for certain things in a certain order
• This is where "elif" comes in 
• it stands for ELSE IF
• you only check the elif when the first if has failed
• you can then add as many of these as you like
• and they get checked in order until one if met
• if none are met then the code under the ELSE part will run
• ELSE will only EVER RUN when the IF and ELIFs have all failed

PREDICT

RUN

try running the code

Investigate and Modify

With this code try and:

• Edit the names and responses the code is looking for in the various statements
• add an additional elif statement to look for an additional name (maybe yours)

MAKE

Make your own version of an if/elif/else statement which:

• Has a procedure defined appropriately
• asks the user to enter a favourite animal
• checks the animal against 4 different animals, each with a specific response if they are selected
• prints that it doesn't like the animal if it is not one of these 4
• calls the written procedure in the main code routine
• You can use this blank

Debugging task

Try and fix these faulty if statements