Reusable code
Reusable code means writing the logic once and calling it by name. If the logic later turns out to be wrong, there is one place to fix instead of nine.
Python for Kids · Class 6 · Module 5 of 9
Functions as Building Blocks
A function is a spell you write once and can then cast whenever you like.
8 sessionsSessions 33–40
4 weeksTypical pace
BeginnerLevel
Class 6Python & Coding
The big idea
Functions let students wrap a useful chunk of work in a name, hand it information, and get an answer back. Programs stop being one long scroll and start being a set of named parts that can be built and tested separately.
Why it matters
This is the first real engineering habit: solve a problem once, name it well, and reuse it. It is also the skill that makes larger projects possible at all.
Unpacked
What you will actually learn
Three core ideas, each taught with worked examples and then practised until it feels obvious.
Parameters
Parameters are the slots a function leaves open for information. greet("Aarav") and greet("Meera") run the same code with different inputs.
Return values
return hands a value back to whoever called the function, so the answer can be stored, printed or fed into the next calculation. Printing and returning are not the same thing.
Did you know?
Professional codebases are judged less on cleverness than on naming. A function called calculate_total_price is worth more than one called ctp.
Common mix-up
“print and return do the same job.” print shows a value to a human; return gives it back to the program. Mixing them up breaks maths chains silently.
Session by session
Your 8-session journey
Sessions 33–40 of the 72-session year, at two one-hour sessions per week.
- 1
Warm-up and big picture
Where this module fits, what you will build, and a hands-on starter that gets everyone curious about reusable code.
- 2
Reusable code
Guided teaching on reusable code, worked through together with the teacher.
- 3
Reusable code — practice lab
Independent practice, small challenges and one deliberate mistake to diagnose.
- 4
Parameters
Guided teaching on parameters, building directly on the previous two sessions.
- 5
Parameters — practice lab
Applied tasks that combine reusable code and parameters in one piece of work.
- 6
Return values
Return values introduced and practised, completing the toolkit needed for the project.
- 7
Project build
Guided build session for the module project: Mini calculator toolkit.
- 8
Test, present and reflect
Finish, test against the checklist, present the work and explain the decisions behind it.
Project lab
Mini calculator toolkit
Every module ends with something the student built themselves and can demonstrate. This is the piece that goes into their portfolio and gets explained out loud at the end of session 40.
Try this at home
Build a small toolkit of four functions — area of a rectangle, average of three numbers, Celsius to Fahrenheit, and a percentage — then use them all in one menu program.
It is finished when
- It works from start to finish without breaking
- You can explain every part of it in your own words
- You tested it and improved at least one thing afterwards
- Someone else used or understood it without your help
By the end of this module
Students finishing Module 5 can:
- Explain and use reusable code without prompting
- Explain and use parameters without prompting
- Explain and use return values without prompting
- Build and finish mini calculator toolkit
- Test your own work and correct what you find
- Talk an adult through what you made and why
Word bank
The vocabulary introduced here, in plain language:
- function
- A named, reusable block of code.
- parameter
- An input slot a function accepts.
- return
- The value a function sends back.
Module challenge
Think you have got this?
0 XPLevel 1 · Curious Beginner
6 quick questions drawn from this module — vocabulary, the project you build, and a myth-or-fact round. Every wrong answer explains itself, so a mistake still teaches you something.
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