IGCSE Computer Science (9–1) 0984 · Topic 1

Data representation: past paper questions

122 real questionsasked in 10 of the last 10 exam series2019–2026usually: Give, Explain, State, Complete, Convert

Real questions on data representation

The newest 20 of 122 written questions. Open one to see it on the real paper.

0984/11 · May/June 2026 · Q1a[1]
Tick (“) one box to show which is the largest unit of measurement for data storage. A. exbibyte (EiB) B gibibyte (GiB) C_ mebibyte (MiB) D_tebibyte (TiB)
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0984/11 · May/June 2026 · Q1c[1]
Data is converted to binary to be stored by a computer. Tick (“) one box to show the correct statement about why data is converted to binary for storing in a computer. A Binary uses numbers and characters to store all the data. B_ Binary is one type of data that a computer can store. C_ Data is processed by logic gates...
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0984/11 · May/June 2026 · Q3a[1]
Give one other example of a number system.
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0984/11 · May/June 2026 · Q3f[4]
Add the binary numbers 10011101 and 11110000 using binary addition. Give your answer in binary. Show all your working. 10011101 + 11110000
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0984/11 · May/June 2026 · Q8a[3]
Explain how the computer represents the text.
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0984/11 · May/June 2026 · Q8b(i)[5]
(i) Complete the table with the missing terms and descriptions about sound and images. term description the smallest unit of an image that is made up of one colour SOUNd SAMPIE .......... the dimensions of an image Colour depth .......... the number of samples that are recorded each second
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0984/11 · May/June 2026 · Q8b(ii)[2]
The student wants to compress the video. Give two methods of compression that the student could use to compress the video.
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0984/12 · May/June 2026 · Q1b[1]
The smartwatch stores data that is displayed for the user. Identify the smallest unit of data that is stored by the smartwatch.
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0984/12 · May/June 2026 · Q1c(i)[1]
Tick (W) one box to show whether two’s complement is a base 2, base 8, base 10 or base 16 number system. A base 2 B_ base 8 C_ base 10 D_ base 16
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0984/12 · May/June 2026 · Q1c(ii)[1]
Give the two’s complement 8-bit binary integer that would be stored for the temperature of 32 degrees Celsius.
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0984/12 · May/June 2026 · Q1c(iii)[1]
(iii) Give the two’s complement 8-bit binary integer that would be stored for the temperature of -14 degrees Celsius. working space
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0984/12 · May/June 2026 · Q3a[1]
Tick (“) one box to show which statement is incorrect about why hexadecimal is used to display the error codes. A Hexadecimal is easier to debug than binary. B_ Hexadecimal is easier to read than binary. C Hexadecimal uses less screen space than binary. D_ Hexadecimal uses less storage space than binary.
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0984/12 · May/June 2026 · Q3b[2]
There is a problem with streaming a video and the error codes 152 and 30F are displayed. Convert the two hexadecimal error codes to binary numbers.
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0984/12 · May/June 2026 · Q3g(i)[2]
Give two reasons why the video streaming service chose lossless compression instead of lossy compression.
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0984/12 · May/June 2026 · Q3g(ii)[1]
Give one advantage to the video streaming service of choosing lossy compression instead of lossless compression to compress the videos.
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0984/12 · May/June 2026 · Q6a[3]
Explain how the image is converted to binary for processing by the smartphone.
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0984/21 · May/June 2026 · Q3[3]
Complete the table by writing the most appropriate data type for each variable described. variable description example data data type Age the age of the student 16 TelephoneNumber | the telephone number of | . 44 7946398573 the student Teenager whether the student is a TRUE teenager or not
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0984/22 · May/June 2026 · Q2[1]
Tick (W) one box to identify a programming data type used to store a single letter, symbol or number input from the keyboard. A Boolean B_ char C integer Dreal
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0984/22 · May/June 2026 · Q7a[1]
State one reason to store data in a file.
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0984/22 · May/June 2026 · Q7b[4]
Alist of names of the members of a club are stored in a file called Names. txt Write the pseudocode statements to load a line of text from Names. txt and assign the line of text to an appropriately named variable.
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What examiners said

Many candidates were able to identify the correct data storage unit. The most common incorrect answer given was ‘byte’.
— Examiner report, May/June 2025, 0984/11 Q1(a) (Cambridge)

Some candidates were able to give the correct number of tebibytes. Some candidates attempted to multiply 1024 by 1024 instead of multiplying it by 2.
— Examiner report, May/June 2025, 0984/11 Q1(b) (Cambridge)

Most candidates were able to state that compression would be used. Types of compression such as lossy and lossless were also accepted.
— Examiner report, May/June 2025, 0984/11 Q1(c)(i) (Cambridge)

Practise this topic

Answer these questions online and get each one marked against the official mark scheme, with what you missed and how to fix it.

Download 0984 papers

In the syllabus

1 0478.1.0.01 — Understand how data is encrypted using • Asymmetric encryption includes the use of

Understand how data is encrypted using • Asymmetric encryption includes the use of
public and private keys
Understand what is meant by, and the purpose • A network interface card is given a MAC
address at the point of manufacture
• MAC addresses are usually written as hexadecimal • MAC addresses are created using the manufacturer code and the serial code
(a) Understand what is meant by, and the • An IP address is allocated by the network and it
can be static or dynamic
Understand that there are different types of • Including the characteristics of, and differences
between, IPv4 and IPv6
Describe the role of a router in a network • A router sends data to a specific destination on a network • A router can assign IP addresses • A router can connect a local network to the internet
Describe the advantages and disadvantages of • Including scenarios from:
– industry – transport – agriculture – weather – gaming – lighting – science

2 0478.1.0.02 — public and private keys

public and private keys

3 0478.1.0.03 — Understand what is meant by, and the purpose • A network interface card is given a MAC

Understand what is meant by, and the purpose • A network interface card is given a MAC

4 0478.1.0.04 — address at the point of manufacture

address at the point of manufacture

5 0478.1.0.05 — • MAC addresses are usually written as hexadecimal • MAC addresses are created using the manufacturer code and the serial code

• MAC addresses are usually written as hexadecimal • MAC addresses are created using the manufacturer code and the serial code

6 0478.1.0.06 — (a) Understand what is meant by, and the • An IP address is allocated by the network and it

(a) Understand what is meant by, and the • An IP address is allocated by the network and it

7 0478.1.0.07 — can be static or dynamic

can be static or dynamic

8 0478.1.0.08 — Understand that there are different types of • Including the characteristics of, and differences

Understand that there are different types of • Including the characteristics of, and differences

9 0478.1.0.09 — between, IPv4 and IPv6

between, IPv4 and IPv6

10 0478.1.0.10 — Describe the role of a router in a network • A router sends data to a specific destination on a network • A router can assign IP addresses •

Describe the role of a router in a network • A router sends data to a specific destination on a network • A router can assign IP addresses • A router can connect a local network to the internet

11 0478.1.0.11 — Describe the advantages and disadvantages of • Including scenarios from:

Describe the advantages and disadvantages of • Including scenarios from:

12 0478.1.0.12 — – industry – transport – agriculture – weather – gaming – lighting – science

– industry – transport – agriculture – weather – gaming – lighting – science

13 0478.1.0.13 — Understand and use basic data types • Including: – integer – real – char – string – Boolean

Understand and use basic data types • Including: – integer – real – char – string – Boolean

14 0478.1.0.14 — Understand the use of arrays • Including the use of variables as indexes in arrays

Understand the use of arrays • Including the use of variables as indexes in arrays

15 0478.1.0.15 — Write values into, and read values from, an • The first index can be zero or one

Write values into, and read values from, an • The first index can be zero or one

16 0478.1.0.16 — • Including nested iteration

• Including nested iteration

17 0478.1.0.17 — Open, close and use a file for reading and • Including:

Open, close and use a file for reading and • Including:

18 0478.1.0.18 — – read and write single items of data – read and write a line of text

– read and write single items of data – read and write a line of text

19 0478.1.1.01 — Understand how and why computers use • Any form of data needs to be converted to

Understand how and why computers use • Any form of data needs to be converted to
binary to be processed by a computer • Data is processed using logic gates and stored in registers
(a) Understand the denary, binary and • Denary is a base 10 system
• Binary is a base 2 system • Hexadecimal is a base 16 system
• Values used will be integers only
positive denary and positive binary • Conversions in both directions, e.g. denary to
positive denary and positive binary or binary to denary
• Maximum binary number length of 16-bit
positive hexadecimal and positive
Understand how and why hexadecimal is used • Areas within computer science that
hexadecimal is used should be identified • Hexadecimal is easier for humans to understand than binary, as it is a shorter representation of binary
(a) Add two positive 8-bit binary integers

20 0478.1.1.02 — binary to be processed by a computer • Data is processed using logic gates and stored in registers

binary to be processed by a computer • Data is processed using logic gates and stored in registers

21 0478.1.1.03 — (a) Understand the denary, binary and • Denary is a base 10 system

(a) Understand the denary, binary and • Denary is a base 10 system

22 0478.1.1.04 — • Binary is a base 2 system • Hexadecimal is a base 16 system

• Binary is a base 2 system • Hexadecimal is a base 16 system

23 0478.1.1.05 — • Values used will be integers only

• Values used will be integers only

24 0478.1.1.06 — positive denary and positive binary • Conversions in both directions, e.g. denary to

positive denary and positive binary • Conversions in both directions, e.g. denary to

25 0478.1.1.07 — positive denary and positive binary or binary to denary

positive denary and positive binary or binary to denary

26 0478.1.1.08 — • Maximum binary number length of 16-bit

• Maximum binary number length of 16-bit

27 0478.1.1.09 — positive hexadecimal and positive

positive hexadecimal and positive

28 0478.1.1.10 — Understand how and why hexadecimal is used • Areas within computer science that

Understand how and why hexadecimal is used • Areas within computer science that

29 0478.1.1.11 — hexadecimal is used should be identified • Hexadecimal is easier for humans to understand than binary, as it is a shorter representation of

hexadecimal is used should be identified • Hexadecimal is easier for humans to understand than binary, as it is a shorter representation of binary

30 0478.1.1.12 — (a) Add two positive 8-bit binary integers

(a) Add two positive 8-bit binary integers

31 0478.1.1.13 — Understand the concept of overflow and • An overflow error will occur if the value is

Understand the concept of overflow and • An overflow error will occur if the value is

32 0478.1.1.14 — greater than 255 in an 8-bit register • A computer or a device has a predefined limit that it can represent or store, for example 16-bit • A

greater than 255 in an 8-bit register • A computer or a device has a predefined limit that it can represent or store, for example 16-bit • An overflow error occurs when a value outside this limit should be returned

33 0478.1.1.15 — Perform a logical binary shift on a positive 8-bit • Perform logical left shifts

Perform a logical binary shift on a positive 8-bit • Perform logical left shifts

34 0478.1.1.16 — • Perform logical right shifts

• Perform logical right shifts

35 0478.1.1.17 — • Perform multiple shifts • Bits shifted from the end of the register are lost and zeros are shifted in at the opposite end of the register

• Perform multiple shifts • Bits shifted from the end of the register are lost and zeros are shifted in at the opposite end of the register • The positive binary integer is multiplied or divided according to the shift performed • The most significant bit(s) or least significant bit(s) are lost

36 0478.1.1.18 — Use the two’s complement number system to • Convert a positive binary or denary integer to a

Use the two’s complement number system to • Convert a positive binary or denary integer to a

37 0478.1.1.19 — two’s complement 8-bit integer and vice versa

two’s complement 8-bit integer and vice versa

38 0478.1.1.20 — • Convert a negative binary or denary integer to a two’s complement 8-bit integer and vice versa

• Convert a negative binary or denary integer to a two’s complement 8-bit integer and vice versa

39 0478.1.2.01 — Understand how and why a computer • Text is converted to binary to be processed by

Understand how and why a computer • Text is converted to binary to be processed by
a computer
• Unicode allows for a greater range of
characters and symbols than ASCII, including different languages and emojis • Unicode requires more bits per character than ASCII
Understand how and why a computer • A sound wave is sampled for sound to be
converted to binary, which is processed by a
computer • The sample rate is the number of samples taken in a second • The sample resolution is the number of bits per sample • The accuracy of the recording and the file size increases as the sample rate and resolution increase
Understand how and why a computer • An image is a series of pixels that are converted
to binary, which is processed by a computer
• The resolution is the number of pixels in the image • The colour depth is the number of bits used to represent each colour • The file size and quality of the image increase as the resolution and colour depth increase

40 0478.1.2.02 — a computer

a computer

41 0478.1.2.03 — • Unicode allows for a greater range of

• Unicode allows for a greater range of

42 0478.1.2.04 — characters and symbols than ASCII, including different languages and emojis • Unicode requires more bits per character than ASCII

characters and symbols than ASCII, including different languages and emojis • Unicode requires more bits per character than ASCII

43 0478.1.2.05 — Understand how and why a computer • A sound wave is sampled for sound to be

Understand how and why a computer • A sound wave is sampled for sound to be

44 0478.1.2.06 — converted to binary, which is processed by a

converted to binary, which is processed by a

45 0478.1.2.07 — computer • The sample rate is the number of samples taken in a second • The sample resolution is the number of bits per sample • The accurac

computer • The sample rate is the number of samples taken in a second • The sample resolution is the number of bits per sample • The accuracy of the recording and the file size increases as the sample rate and resolution increase

46 0478.1.2.08 — Understand how and why a computer • An image is a series of pixels that are converted

Understand how and why a computer • An image is a series of pixels that are converted

47 0478.1.2.09 — to binary, which is processed by a computer

to binary, which is processed by a computer

48 0478.1.2.10 — • The resolution is the number of pixels in the image • The colour depth is the number of bits used to represent each colour • The file size

• The resolution is the number of pixels in the image • The colour depth is the number of bits used to represent each colour • The file size and quality of the image increase as the resolution and colour depth increase

49 0478.1.3.01 — Understand how data storage is measured • Including: – bit – nibble – byte – kibibyte (KiB) – mebibyte (MiB) – gibibyte (GiB) – tebibyte (Ti

Understand how data storage is measured • Including: – bit – nibble – byte – kibibyte (KiB) – mebibyte (MiB) – gibibyte (GiB) – tebibyte (TiB) – pebibyte (PiB) – exbibyte (EiB) • The amount of the previous denomination present in the data storage size, e.g.: – 8 bits in a byte – 1024 mebibytes in a gibibyte
Calculate the file size of an image file and a • Answers must be given in the units specified
in the question
Calculations must use the measurement of 1024 and not 1000 • Information given may include: – image resolution and colour depth – sound sample rate, resolution and length of track
Understand the purpose of and need for data • Compression exists to reduce the size of the file
• What the impact of this is, e.g.: – less bandwidth required – less storage space required – shorter transmission time
Understand how files are compressed using • Lossy compression reduces the file size by
permanently removing data, e.g. reducing resolution or colour depth, reducing sample rate or resolution • Lossless compression reduces the file size without permanent loss of data, e.g. run length encoding (RLE)

50 0478.1.3.02 — Calculate the file size of an image file and a • Answers must be given in the units specified

Calculate the file size of an image file and a • Answers must be given in the units specified

51 0478.1.3.03 — in the question

in the question

52 0478.1.3.04 — Calculations must use the measurement of 1024 and not 1000 • Information given may include: – image resolution and colour depth – sound samp

Calculations must use the measurement of 1024 and not 1000 • Information given may include: – image resolution and colour depth – sound sample rate, resolution and length of track

53 0478.1.3.05 — Understand the purpose of and need for data • Compression exists to reduce the size of the file

Understand the purpose of and need for data • Compression exists to reduce the size of the file

54 0478.1.3.06 — • What the impact of this is, e.g.: – less bandwidth required – less storage space required – shorter transmission time

• What the impact of this is, e.g.: – less bandwidth required – less storage space required – shorter transmission time

55 0478.1.3.07 — Understand how files are compressed using • Lossy compression reduces the file size by

Understand how files are compressed using • Lossy compression reduces the file size by

56 0478.1.3.08 — permanently removing data, e.g. reducing resolution or colour depth, reducing sample rate or resolution • Lossless compression reduces the f

permanently removing data, e.g. reducing resolution or colour depth, reducing sample rate or resolution • Lossless compression reduces the file size without permanent loss of data, e.g. run length encoding (RLE)

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