IGCSE Computer Science 0478 — 7b Decomposition and Sub-systems
Breaking a big problem into parts a computer can handle.
Modules (47)
1
Digital system
2
Sub-system
3
Sub-systems made of further sub-systems
4
Input, process, output and storage
5
Decomposing a problem into sub-problems
6
Component parts of a problem: inputs
7
Component parts of a problem: processes
8
Component parts of a problem: outputs
9
Component parts of a problem: storage
10
Splitting a scenario into inputs, processes, outputs and storage
11
Writing an IPO chart for a program
12
Why decomposition helps: easier to understand and solve
13
Why decomposition helps: testing each part separately
14
Why decomposition helps: team work and reuse
15
Program development life cycle
16
The analysis stage: problem and requirements
17
Abstraction (7b)
18
Deciding which details to keep and which to ignore
19
Applying abstraction to a scenario
20
Decomposition diagrams
21
Structure diagram
22
Drawing a structure diagram from a scenario
23
Completing and reading a structure diagram
24
Algorithm
25
Choosing a design method: structure diagram, flowchart or pseudocode
26
Cambridge flowchart symbols (7b)
27
Drawing a sequence in a flowchart
28
Input and output shapes in a flowchart
29
Drawing a decision in a flowchart
30
Drawing a loop in a flowchart
31
The subroutine symbol in a flowchart
32
Turning a structure diagram into a main flowchart and sub-flowcharts
33
What is Pseudocode
34
Cambridge pseudocode: keywords in capitals and indentation
35
Pseudocode assignment: ←
36
Pseudocode INPUT and OUTPUT
37
Pseudocode IF ... THEN ... ELSE ... ENDIF
38
Pseudocode FOR ... TO ... NEXT loop
39
Pseudocode WHILE ... DO ... ENDWHILE and REPEAT ... UNTIL
40
Procedures versus functions
41
Pseudocode PROCEDURE ... ENDPROCEDURE and CALL
42
Pseudocode FUNCTION ... RETURNS ... RETURN ... ENDFUNCTION
43
Functions calling other functions
44
Writing a main program that calls one procedure per sub-problem
45
Turning a structure diagram into pseudocode
46
Constructing a full solution: decompose, draw and write
47
Writing exam answers about decomposition and abstraction
Smaller journeys, one per content description
The same modules, split up so a class can take just the content description it's working on.
14
IGCSE Computer Science 0478: Sub-systems and decomposing a problem
Students learn that every computer system is made of sub-systems and how to decompose a problem into inputs, processes, outputs and storage, and why that makes it easier to solve.
5
IGCSE Computer Science 0478: Development life cycle and abstraction
Students learn the four stages of the program development life cycle and use abstraction in analysis to keep only the detail that matters.
28
IGCSE Computer Science 0478: Designing solutions with structure diagrams, flowcharts and pseudocode
Students design and construct solutions using structure diagrams, Cambridge flowchart symbols and Cambridge pseudocode, then link them into one decomposed solution and practise exam answers.
Printables for this journey
Every module above has its own free printable worksheet with an answer key. These crosswords and word searches cover the same terms:
✎
VCE Pseudocode Crossword: What is Pseudocode to if-then block (Modules 1–10)
6 clues · What is Pseudocode, Pseudocode Writing Conventions, Variable Assignment: x <- value, input keyword and more
🔎
VCE Pseudocode Word Search: What is Pseudocode to Reading and tracing complex pseudocode (Modules 1–28)
20 words to find · What is Pseudocode, Pseudocode Writing Conventions, Variable Assignment: x <- value, input keyword and more
✎
Years 5–6 Digital Systems Crossword: Inside digital systems (Modules 1–10)
10 clues · Digital system, Hardware, Software, Input, process, output and storage and more
🔎
Years 5–6 Digital Systems Word Search: Inside digital systems and Data and networks (Modules 1–20)
20 words to find · Digital system, Hardware, Software, Input, process, output and storage and more
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Years 5–6 Creating Digital Solutions Crossword: Defining problems and requirements and Designing algorithms with branching and iteration (Modules 1–10)
10 clues · What is a problem a digital system can solve?, User need, Writing a problem statement, Functional requirements and more
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Years 5–6 Creating Digital Solutions Crossword: Designing algorithms with branching and iteration and Designing user interfaces (Modules 21–30)
10 clues · Branching inside a loop, Algorithms that use sequence, branching and iteration together, Drawing a sequence in a flowchart, Drawing a decision in a flowchart and more
🔎
Years 5–6 Creating Digital Solutions Word Search: Defining problems and requirements and Designing algorithms with branching and iteration (Modules 1–20)
20 words to find · What is a problem a digital system can solve?, User need, Writing a problem statement, Functional requirements and more
🔎
Years 5–6 Creating Digital Solutions Word Search: Designing algorithms with branching and iteration and Designing user interfaces (Modules 21–40)
20 words to find · Branching inside a loop, Algorithms that use sequence, branching and iteration together, Drawing a sequence in a flowchart, Drawing a decision in a flowchart and more
✎
VCE Software Development U4O1 Crossword: Efficient and effective solutions and user-centred design to Classes, objects and access modifiers (Modules 3–79)
10 clues · User-centred design, Order of operations with brackets in Python, Choosing data types for input, storage and output, Procedures versus functions and more
🔎
VCE Software Development U4O1 Word Search: Efficient and effective solutions and user-centred design to Code repositories, APIs, libraries and AI assistants (Modules 3–114)
20 words to find · User-centred design, Order of operations with brackets in Python, Choosing data types for input, storage and output, Procedures versus functions and more
✎
Years 7–8 Creating Digital Solutions Crossword: Defining and decomposing problems and Designing and tracing algorithms (Modules 3–47)
10 clues · Interviewing a user, Decomposing a problem into sub-problems, Decomposition diagrams, Non-functional requirements and more
🔎
Years 7–8 Creating Digital Solutions Word Search: Defining and decomposing problems to Evaluating digital solutions (Modules 3–125)
21 words to find · Interviewing a user, Decomposing a problem into sub-problems, Decomposition diagrams, Non-functional requirements and more
✎
VCE Applied Computing U1O2 Crossword: Requirements and design tools to Naming conventions and internal documentation (Modules 8–88)
10 clues · Writing an IPO chart for a program, Accessing record fields by index, Abstraction in OOP, Encapsulation in OOP and more
🔎
VCE Applied Computing U1O2 Word Search: Requirements and design tools to Legal requirements and emerging trends (Modules 8–124)
21 words to find · Writing an IPO chart for a program, Accessing record fields by index, Abstraction in OOP, Encapsulation in OOP and more
✎
Crossword: 7b Decomposition and Sub-systems (Modules 94–106)
10 clues · Sub-system, Sub-systems made of further sub-systems, Component parts of a problem: inputs, Component parts of a problem: processes and more
✎
Crossword: 7b Decomposition and Sub-systems (Modules 107–118)
10 clues · Program development life cycle, The analysis stage: problem and requirements, Abstraction (7b), Deciding which details to keep and which to ignore and more
✎
Crossword: 7b Decomposition and Sub-systems (Modules 123–134)
10 clues · The subroutine symbol in a flowchart, Turning a structure diagram into a main flowchart and sub-flowcharts, Cambridge pseudocode: keywords in capitals and indentation, Pseudocode assignment: ← and more
✎
Crossword: 7b Decomposition and Sub-systems and 7c Pseudocode and Flowcharts (Modules 136–145)
10 clues · Writing a main program that calls one procedure per sub-problem, Turning a structure diagram into pseudocode, Constructing a full solution: decompose, draw and write, Writing exam answers about decomposition and abstraction and more
🔎
Word Search: 7b Decomposition and Sub-systems (Modules 94–118)
21 words to find · Sub-system, Sub-systems made of further sub-systems, Component parts of a problem: inputs, Component parts of a problem: processes and more
🔎
Word Search: 7b Decomposition and Sub-systems and 7c Pseudocode and Flowcharts (Modules 123–145)
20 words to find · The subroutine symbol in a flowchart, Turning a structure diagram into a main flowchart and sub-flowcharts, Cambridge pseudocode: keywords in capitals and indentation, Pseudocode assignment: ← and more
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This curriculum is aligned to the Australian Curriculum (ACARA) and Victorian Curriculum, spanning roughly Years 3 to 10 — from first sequencing and variables through to object-oriented programming and advanced data structures. Start wherever matches your class's current level; each module builds on the last.
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Do I need to know IGCSE Computer Science Paper 2 myself to teach this?
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