AQA GCSE Computer Science past paper questions, worked and runnable

AQA GCSE Computer Science (8525) Paper 1 past paper questions: trace tables, programs to write, algorithms to complete and fix. Each one is worked through step by step and can be run in your browser, with the lesson that teaches it.

AQA 852563 worked answers5 papersfree

Paper 1 is where the programming marks are: tracing, fixing and writing code. For each question below we say what it tests and link the lesson that teaches it. Where it says Worked answer, the question is gone through step by step, with a program you can run. We do not host the papers. Each one is linked on AQA's own site.

By type of question

Write a program

Read the code

Trace table

Complete the algorithm

Fix the code

Explain

Testing

Paper by paper

June 2025, Paper 1B (Python)

Sat 12 May 2025, 90 marks. On AQA's site: question paper, mark scheme.

Question	What it tests	Type	Marks	Learn it
1	Operators in a short program, and a trace of a while loop that doubles	Trace table	7	F13.2 Trace tables F2.6 Condition-controlled loops: while F1.9 Arithmetic operators	Worked answer
2	A loyalty card with MOD and elif, and the value of the free items	Complete the algorithm	7	F2.3 else, elif and Boolean operators F1.9 Arithmetic operators F1.7 Input from the user	Worked answer
3	A coaching cost with three price bands	Write a program	8	F2.3 else, elif and Boolean operators F2.4 Nested selection and match F13.4 Programming questions	Worked answer
4	Validate a name by length until it is accepted, test data, and a username flowchart	Write a program	13	F6.1 Defensive design and validation F6.3 Testing and test data F5.2 Flowcharts	Worked answer
5	Data types, and five inputs rewritten as a loop with one	Write a program	8	F1.8 Data types and casting F2.5 Count-controlled loops: for F2.7 Loop patterns	Worked answer
6	Show a bubble sort and a merge, compare them, and justify a binary search	Explain	10	F5.7 Bubble sort F5.9 Merge sort and comparing algorithms F5.6 Binary search	Worked answer
7	Read a subroutine: purpose, outputs, return value, parameter	Read the code	7	F4.2 Parameters and return values F4.4 Decomposition and abstraction F1.9 Arithmetic operators	Worked answer
8	Trace a loop that compares two binary strings with OR, NOT and AND	Trace table	6	F13.2 Trace tables F3.1 String handling F2.3 else, elif and Boolean operators	Worked answer
9	Which of five algorithms correctly total an array	Read the code	2	F3.4 Iterating over a list F6.4 Debugging logic errors F2.6 Condition-controlled loops: while	Worked answer
10	Records, and the smallest value in an array without min or sort	Write a program	8	F3.6 Records F2.7 Loop patterns F13.4 Programming questions	Worked answer
11	Trace findLetter, then write the word game that calls it	Write a program	14	F4.2 Parameters and return values F3.1 String handling F13.4 Programming questions	Worked answer

June 2024, Paper 1B (Python)

Sat 15 May 2024, 90 marks. On AQA's site: question paper, mark scheme.

Question	What it tests	Type	Marks	Learn it
1	LEN, POSITION, a data type, assignment, and a two line program	Read the code	6	F3.1 String handling F1.6 Variables, constants and assignment F1.7 Input from the user	Worked answer
2	Follow an IF, ELSEIF chain with NOT, OR, AND and MOD	Read the code	5	F2.3 else, elif and Boolean operators F1.9 Arithmetic operators	Worked answer
3	random.randrange, a test plan, and a syntax and a logic error	Testing	6	F3.7 Random numbers F6.3 Testing and test data F1.4 Errors: syntax, runtime and logic	Worked answer
4	Define abstraction and name decomposition	Short answer	2	F4.4 Decomposition and abstraction
5	The output of a nested IF for three pairs of inputs	Read the code	3	F2.4 Nested selection and match F13.2 Trace tables	Worked answer
6	Essay marks with penalties for late essays, never below 0	Write a program	7	F2.3 else, elif and Boolean operators F1.7 Input from the user F13.4 Programming questions	Worked answer
7	Build a stock code with string indexing and concatenation	Write a program	4	F3.1 String handling F1.7 Input from the user	Worked answer
8	Trace a loop over three arrays that uses DIV	Trace table	6	F13.2 Trace tables F3.4 Iterating over a list F1.9 Arithmetic operators	Worked answer
9	A data structure, a RECORD definition, and the dearer of two books	Complete the algorithm	7	F3.6 Records F2.3 else, elif and Boolean operators	Worked answer
10	Trace three subroutines that call each other	Read the code	2	F4.2 Parameters and return values F4.3 Local and global variables	Worked answer
11	Authenticate against two username and password pairs until valid	Write a program	7	F6.2 Authentication F2.6 Condition-controlled loops: while F13.4 Programming questions	Worked answer
12.1 to 12.5	A sliding puzzle: move tiles, and read nested loops that find the blank	Read the code	7	F3.5 Two-dimensional arrays F4.2 Parameters and return values	Worked answer
12.6, 12.7	Use given subroutines to check a row and to play until solved	Write a program	10	F4.2 Parameters and return values F2.6 Condition-controlled loops: while F13.4 Programming questions	Worked answer
13	Explain how a linear search works	Explain	3	F5.5 Linear search
14	Local variables, and a subroutine that counts busy days and returns the count	Write a program	7	F4.1 Writing functions F4.3 Local and global variables F2.7 Loop patterns	Worked answer
15	Move 1 or 2 along a row of cells, back to 0 on an X or past the end	Write a program	8	F3.3 Lists: one-dimensional arrays F2.6 Condition-controlled loops: while F13.4 Programming questions	Worked answer

June 2023, Paper 1B (Python)

Sat 19 May 2023, 90 marks. On AQA's site: question paper, mark scheme.

Question	What it tests	Type	Marks	Learn it
1.1	Define the term algorithm	Short answer	2	F5.1 What an algorithm is
1.2 to 1.5	String handling: length, joining, substring, position of a character	Multiple choice	4	F3.1 String handling
2	Read a nested WHILE loop that uses integer division	Read the code	3	F2.6 Condition-controlled loops: while F1.9 Arithmetic operators	Worked answer
3	One advantage of the structured approach	Short answer	2	F4.4 Decomposition and abstraction
4	Trace a Python function with three sets of inputs, then make it robust	Trace table	4	F13.2 Trace tables F4.2 Parameters and return values F6.1 Defensive design and validation	Worked answer
5	Trace a flowchart with a loop	Trace table	3	F5.4 Trace tables F5.2 Flowcharts F13.2 Trace tables	Worked answer
6	Fill the gaps in a login routine	Complete the algorithm	4	F6.2 Authentication F2.6 Condition-controlled loops: while	Worked answer
7	A ticket price with a group discount	Write a program	6	F2.2 Selection: if F1.7 Input from the user F13.4 Programming questions	Worked answer
8	Explain how merge sort works	Explain	4	F5.9 Merge sort and comparing algorithms
9	Records: fields, assignment, looping over an array of records	Read the code	4	F3.6 Records
10	Trace nested FOR loops over a list of scores and find the error	Trace table	6	F13.2 Trace tables F2.7 Loop patterns F6.4 Debugging logic errors	Worked answer
11	Normal, erroneous and boundary test data, and a logic error	Testing	5	F6.3 Testing and test data F6.4 Debugging logic errors	Worked answer
12.1	Trace a binary search	Trace table	4	F5.6 Binary search F13.2 Trace tables	Worked answer
12.2	Write your own linear search	Write a program	7	F5.5 Linear search F3.4 Iterating over a list F13.4 Programming questions	Worked answer
12.3	Why binary search cannot be used on an unsorted list	Short answer	1	F5.6 Binary search
12.4	Fix a subroutine's parameter and a FOR loop that counts down	Fix the code	3	F4.2 Parameters and return values F2.5 Count-controlled loops: for	Worked answer
13	Validate a grid reference until it is correct	Write a program	6	F6.1 Defensive design and validation F3.1 String handling F13.4 Programming questions	Worked answer
14	Fill the gaps in an algorithm that uses a two-dimensional array	Complete the algorithm	3	F3.5 Two-dimensional arrays F4.2 Parameters and return values	Worked answer
15	Share a bill: loop until it is paid, then report the tip	Write a program	8	F2.6 Condition-controlled loops: while F2.3 else, elif and Boolean operators F13.4 Programming questions	Worked answer
16	A dice game to 21 with random numbers	Write a program	11	F3.7 Random numbers F2.6 Condition-controlled loops: while F13.4 Programming questions	Worked answer

June 2022, Paper 1B (Python)

90 marks. On AQA's site: question paper, mark scheme.

Question	What it tests	Type	Marks	Learn it
1	MOD, selection, assignment, relational operators and a definite loop	Read the code	6	F2.2 Selection: if F1.9 Arithmetic operators F2.5 Count-controlled loops: for	Worked answer
2	Follow a nested IF with AND, then name the data types	Read the code	6	F2.4 Nested selection and match F1.8 Data types and casting	Worked answer
3	Rewrite two lines: concatenate strings, change a calculation	Fix the code	2	F3.1 String handling F1.9 Arithmetic operators	Worked answer
4	Which of two programs is more efficient, and why	Explain	3	F5.1 What an algorithm is F5.9 Merge sort and comparing algorithms	Worked answer
5	A syntax error and a logic error in a random number program	Fix the code	5	F1.4 Errors: syntax, runtime and logic F6.4 Debugging logic errors F3.7 Random numbers	Worked answer
6	Define abstraction and complete a decomposition diagram	Short answer	3	F4.4 Decomposition and abstraction
7	Ask for an email address twice and check that they match	Write a program	5	F1.7 Input from the user F2.2 Selection: if F13.4 Programming questions	Worked answer
8	A bonus payment from items sold and years employed	Write a program	7	F2.3 else, elif and Boolean operators F2.4 Nested selection and match F13.4 Programming questions	Worked answer
9	String indexing, LEN and SUBSTRING	Read the code	5	F3.1 String handling F3.3 Lists: one-dimensional arrays	Worked answer
10	Trace a REPEAT UNTIL loop with DIV, then compare it with WHILE	Trace table	8	F13.2 Trace tables F2.6 Condition-controlled loops: while F5.4 Trace tables	Worked answer
11	Complete a subroutine that works out a sound file's size, local variables, why subroutines	Complete the algorithm	10	F4.2 Parameters and return values F4.3 Local and global variables F8.8 Sound	Worked answer
12	Trace a bubble sort on three items	Trace table	8	F5.7 Bubble sort F13.2 Trace tables	Worked answer
13.1	Keep asking until a number is between 1 and 100	Write a program	4	F6.1 Defensive design and validation F2.6 Condition-controlled loops: while	Worked answer
13.2	Find a run of five in a sorted array of 100 cards	Write a program	6	F3.4 Iterating over a list F2.7 Loop patterns F13.4 Programming questions	Worked answer
14.1	Fill a two-dimensional array with nested WHILE loops	Complete the algorithm	4	F3.5 Two-dimensional arrays F2.6 Condition-controlled loops: while	Worked answer
14.2	Write a subroutine that counts the asterisks on a bingo ticket	Write a program	8	F3.5 Two-dimensional arrays F4.1 Writing functions F13.4 Programming questions	Worked answer

Sample assessment material, Paper 1B (Python)

90 marks. On AQA's site: question paper, mark scheme.

Question	What it tests	Type	Marks	Learn it
1	Define algorithm, and match terms to definitions	Short answer	5	F5.1 What an algorithm is F4.4 Decomposition and abstraction
2	The length of a string and concatenation	Multiple choice	2	F3.1 String handling
3	The dog biscuit algorithm: selection, iteration, subroutine calls and a data type	Read the code	5	F2.3 else, elif and Boolean operators F2.5 Count-controlled loops: for F1.8 Data types and casting	Worked answer
4	Fill the gaps in a program that outputs the larger of two numbers	Complete the algorithm	5	F2.3 else, elif and Boolean operators F1.8 Data types and casting
5	A taxi fare: 2 pounds a passenger plus 1.50 a kilometre	Write a program	7	F1.9 Arithmetic operators F1.8 Data types and casting F1.7 Input from the user	Worked answer
6	Check a password against secret and display Welcome or Not welcome	Write a program	5	F6.2 Authentication F2.2 Selection: if
7	A bubble sort with a swapsMade flag: data type, identifiers, and a trace table	Trace table	10	F5.7 Bubble sort F13.2 Trace tables F1.6 Variables, constants and assignment	Worked answer
8	Output LOWER or NOT LOWER for a character	Write a program	7	F3.1 String handling F2.2 Selection: if F3.2 Character codes and conversion	Worked answer
9	Draw a robot's path through a grid from Forward, TurnLeft and ObjectAhead	Read the code	6	F4.1 Writing functions F2.6 Condition-controlled loops: while	Worked answer
10	Two benefits of the structured approach	Short answer	2	F4.4 Decomposition and abstraction
11	Show the steps of a bubble sort on 3, 5, 1, 4, 2	Explain	5	F5.7 Bubble sort
12	Abstraction, and the details a developer missed in a client's request	Short answer	3	F4.4 Decomposition and abstraction
13	Move blocks between columns with MOVE and HEIGHT, keeping their order	Write a program	10	F4.2 Parameters and return values F2.6 Condition-controlled loops: while F5.1 What an algorithm is	Worked answer
14	Which program also multiplies the numbers from one to five	Multiple choice	1	F2.7 Loop patterns
15	Fix a loop that prints odd numbers so that it works for negative input	Fix the code	4	F6.4 Debugging logic errors F2.6 Condition-controlled loops: while	Worked answer
16	A test plan for a 1 to 10 validation loop	Testing	2	F6.3 Testing and test data
17	The highest common factor program that fails for 4 and 4	Fix the code	3	F6.4 Debugging logic errors F2.6 Condition-controlled loops: while	Worked answer
18	Go-kart braking distance: validate the speed, divide by 5, wet ground	Write a program	8	F6.1 Defensive design and validation F2.6 Condition-controlled loops: while F13.4 Programming questions	Worked answer

The specification

AQA GCSE Computer Science (8525), point by point, with the lesson for each section.

These are our own explanations of published exam questions. It is not written or endorsed by AQA, and the question paper and mark scheme remain AQA's copyright. Read them on AQA's site with the links on this page.