Defining & Calling Functions in Python|Cambridge 0478/ 9618 |PPT|Worksheet|Activity|MCQ|Mark Scheme

Teach functions with a complete lesson that’s ready to go.

Functions are how students move from one long script to organised, reusable code, and subroutines appear in the programming paper every year. This pack takes students from “why split code into parts?” to defining, calling and tracing their own functions with confidence. It is aligned to Cambridge IGCSE / AS/ A Level Computer Science 0478/ 9618 (Programming) and needs no prep.

WHAT’S INCLUDED

• PowerPoint lesson ([X] slides): worked examples, live-code demos and built-in check-for-understanding questions

• Student worksheet ([X] pages): scaffolded tasks from recall, to tracing function calls, to exam-style problems

• Hands-on coding activity: students build programs from small functions, such as a calculator, a grade checker and a menu system

• MCQ quiz ([X] questions): quick-fire questions to check understanding and catch misconceptions

• Answers and full mark scheme: model answers with mark allocations, so marking takes minutes

WHAT STUDENTS WILL LEARN

What a function (subroutine) is, and why programmers use them
Defining a function with def: syntax, colon and indentation
Calling a function and how control passes to it and back
Parameters and arguments, and the difference between them
Returning values with return, and storing the result in a variable
Functions that return a value vs procedures that don’t
Local and global variables, and why scope matters
Calling a function from inside another function
Tracing function calls with a trace table to predict the output
Benefits of subroutines: reuse, readability and easier testing
How Python functions map to PROCEDURE and FUNCTION in Cambridge pseudocode
Common errors: forgetting the brackets when calling, using print instead of return, calling before defining, wrong number of arguments, and changing a local variable and expecting a global one to change

WHY TEACHERS LOVE IT

Exam-focused: questions follow Cambridge command words and mark-scheme style
Targets real misconceptions: the mistakes students make every year, especially print vs return
Differentiated: support tasks plus stretch questions for top-grade students
Non-specialist friendly: clear explanations and full answers included
Flexible: works as a single lesson, homework, cover or revision
Print-and-go: no editing needed (editable PPT included)

PERFECT FOR
Cambridge IGCSE 0478/ AS/A level 9618 teachers, heads of department, non-specialist and cover staff, and students learning independently. It suits ages 14-16 (Year 10-11 / Grade 9-10).

PART OF A FULL SERIES
This pack belongs to my Cambridge 0478 / 9618 Python collection. Check my shop for matching packs on Introduction to Python, variables and data types, operators and expressions, string handling, selection, for loops and range(), while loops, nested loops, arrays and file handling.

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