9618Paper 1 · Theory Fundamentals§1.1, §1.2, §1.3

1. Information Representation

Number systems, BCD, two's complement, character sets, multimedia (bitmap/vector, sound) and file compression.

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Statometer85BankerNext Paper 195%

Marks a paper18.4 · 25%Rank#4 of 12 · #2 on P1Trend · last 12→Full stats

Everything for this topic — study hub

AS Level · 9618 · Paper 1

Statometer — what 33 real papers say about this topic and each of its 4 syllabus bullets

Banker · #4 of 12 in AS Level · recomputed with every new session

Banker#4 of 12 in AS Level#2 on Paper 1→ Steady

Set in nearly every paper and worth a big slice of it — revise first, expect it.

Next Paper 1: 95%; 9 in 10 chance it is set
Marks a paper: 18.4 / 75; 25% of Paper 1 · fair share 13%
Appeared in: 33 / 33; Paper 1 sittings 2021–2026
Last set: May/Jun 2026; 9618/13 · Q6 · 8 marks · 11-series streak

Marks in each of the last 12 Paper 1 sittingsOct/Nov 24 → May/Jun 26

What the papers say

Set in 33 of 33 Paper 1 sittings on the current syllabus — treat it as certain.
Worth about 18.4 marks a paper (25% of Paper 1, 2× its fair share).
Last set May/Jun 2026 · 9618/13 · Q6 for 8 marks — in the most recent series.
Set in each of the last 11 series without a miss.
Steady at around 19.9 marks a paper year on year.
Lives on “Explain” and “Show” — 83% of its questions: full sentences with a reason, not one-word answers.
43% of its questions involve a diagram, table or figure — practise with pen and paper.
Its biggest question so far: 18 marks (May/Jun 2024 · 9618/11 · Q2).
Inside the topic, §1.2 Multimedia carries the most marks (43%) and §1.3 Compression the least (14%).
It is examined mostly as AO1 (Knowledge & understanding, 61%), the rest AO2 (39%) — definitions and descriptions in syllabus words score.
The examiner has commented on 37 of its questions — read “What the examiner said” before you practise.
The single biggest share of Paper 1 among its 8 topics.

Command words

Share of questions using the word (a question can use several). What each wants →

Question shapes

≤ 6 mk17
7–9 mk24
10–12 mk6
13–15 mk9
16+ mk7

Average 9.3 marks a question · 43% with a figure or table · 38% with code · biggest 18 marks

Assessment objectives — how it is examined

Every part of every current-syllabus question filed under Cambridge's AO1 / AO2 / AO3 (from its command word and what it asks you to do), so you know whether this topic pays for definitions, for applying, or for judging and building.

AO1 61%

AO2 39%

AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate

Paper 1 as a whole

Paper 1	Syllabus	Measured
AO1 Knowledge & understanding	60%	68%
AO2 Apply & analyse	40%	32%
AO3 Design, program & evaluate	0%	0%

Syllabus = Cambridge's grid; measured = the bank's current-syllabus papers.

Inside the topic — every syllabus bullet, measured

Each part of each question is filed under the bullet it examines; the numbers are per Paper 1 sitting, exactly like the topic's. Open a bullet for its own Statometer.

1.1Data representation#6 of 25 on Paper 1Banker · 7683% next paper4.2 marks28/33 sittings↗ May/Jun 2026Banker · 7683%
4.2 · 29% of topic28/33May/Jun 2026latest series · ↗
Asked in nearly every paper — the bullet to know cold.Syllabus: binary prefixes (kibi, mebi, gibi, tebi) vs decimal prefixes; binary, denary, hexadecimal, BCD, one's and two's complement; converting between them
Next Paper 1
83%
8 in 10
Marks a paper
4.2
6% of the paper · 29% of the topic
Asked in
28 / 33
Paper 1 sittings · 31 questions
Last asked
May/Jun 2026
9618/13 · Q6 · 6 marks · 11-series streak
Asked in 28 of 33 Paper 1 sittings — about 8 papers in 10.
About 4.2 marks a paper (6% of Paper 1; 29% of the topic's marks across its 4 bullets).
Last asked May/Jun 2026 · 9618/13 · Q6 (6 marks) — in the most recent series.
Asked in each of the last 11 series.
Rising: 3.4 → 4.8 marks a paper.
Usually “Convert” or “Show”.
Biggest chunk of marks so far: 8 in May/Jun 2026 · 9618/11 · Q1.
It is examined mostly as AO2 (Apply & analyse, 74%), the rest AO1 (26%) — you must apply it to the given data or scenario — work it out, trace it, explain it in context.
Last 12 sittings↗ Rising
Assessment objectives
AO1 26%
AO2 74%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Convert74%
Show68%
Complete48%
State42%
Practise its 31 questions Biggest: 8 marks · May/Jun 2026
1.1Binary arithmetic#16 of 25 on Paper 1Regular · 4764% next paper2.1 marks20/33 sittings→ May/Jun 2026Regular · 4764%
2.1 · 15% of topic20/33May/Jun 2026latest series · →
Set most sessions for a few marks; know the definition and one example.Syllabus: addition and subtraction with positive and negative integers; overflow; where BCD and hexadecimal are used; ASCII, extended ASCII and Unicode
Next Paper 1
64%
6 in 10
Marks a paper
2.1
3% of the paper · 15% of the topic
Asked in
20 / 33
Paper 1 sittings · 21 questions
Last asked
May/Jun 2026
9618/13 · Q6 · 2 marks · 5-series streak
Asked in 20 of 33 Paper 1 sittings — about 6 papers in 10.
About 2.1 marks a paper (3% of Paper 1; 15% of the topic's marks across its 4 bullets).
Last asked May/Jun 2026 · 9618/13 · Q6 (2 marks) — in the most recent series.
Asked in each of the last 5 series.
Usually “Show” or “Convert”.
Biggest chunk of marks so far: 6 in May/Jun 2021 · 9618/12 · Q6.
It is examined mostly as AO1 (Knowledge & understanding, 50%), the rest AO2 (50%) — definitions and descriptions in syllabus words score.
Last 12 sittings→ Steady
Assessment objectives
AO1 50%
AO2 50%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Show67%
Convert62%
Complete48%
State48%
Practise its 21 questions Biggest: 6 marks · May/Jun 2021
1.2Multimedia#3 of 25 on Paper 1Banker · 8784% next paper5.9 marks28/33 sittings↗ May/Jun 2026Banker · 8784%
5.9 · 43% of topic28/33May/Jun 2026latest series · ↗
Asked in nearly every paper — the bullet to know cold.Syllabus: bitmaps (pixel, file header, resolution, colour depth) and file-size estimates; vector graphics (drawing objects, properties, drawing list); sound sampling rate and resolution
Next Paper 1
84%
8 in 10
Marks a paper
5.9
8% of the paper · 43% of the topic
Asked in
28 / 33
Paper 1 sittings · 36 questions
Last asked
May/Jun 2026
9618/13 · Q3 · 8 marks · 11-series streak
Asked in 28 of 33 Paper 1 sittings — about 8 papers in 10.
About 5.9 marks a paper (8% of Paper 1; 43% of the topic's marks across its 4 bullets).
Last asked May/Jun 2026 · 9618/13 · Q3 (8 marks) — in the most recent series.
Asked in each of the last 11 series.
Rising: 5.7 → 6.2 marks a paper.
Usually “Explain” or “Complete”: full sentences with a reason, not one-word answers.
Biggest chunk of marks so far: 12 in Oct/Nov 2021 · 9618/12 · Q5.
It is examined mostly as AO1 (Knowledge & understanding, 73%), the rest AO2 (27%) — definitions and descriptions in syllabus words score.
Last 12 sittings↗ Rising
Assessment objectives
AO1 73%
AO2 27%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Explain69%
Complete47%
Describe47%
Show39%
Practise its 36 questions Biggest: 12 marks · Oct/Nov 2021
1.3Compression#17 of 25 on Paper 1Regular · 4362% next paper1.8 marks21/33 sittings→ May/Jun 2026Regular · 4362%
1.8 · 14% of topic21/33May/Jun 2026latest series · →
Set most sessions for a few marks; know the definition and one example.Syllabus: the need for compression; lossy vs lossless and when to use each; compressing text, bitmaps, vector graphics and sound, including run-length encoding
Next Paper 1
62%
6 in 10
Marks a paper
1.8
2% of the paper · 14% of the topic
Asked in
21 / 33
Paper 1 sittings · 21 questions
Last asked
May/Jun 2026
9618/13 · Q3 · 2 marks · 11-series streak
Asked in 21 of 33 Paper 1 sittings — about 6 papers in 10.
About 1.8 marks a paper (2% of Paper 1; 14% of the topic's marks across its 4 bullets).
Last asked May/Jun 2026 · 9618/13 · Q3 (2 marks) — in the most recent series.
Asked in each of the last 11 series.
Usually “Explain” or “Identify”: full sentences with a reason, not one-word answers.
Biggest chunk of marks so far: 7 in May/Jun 2025 · 9618/11 · Q2.
It is examined almost entirely as AO1 (Knowledge & understanding, 82%) — definitions and descriptions in syllabus words score.
Last 12 sittings→ Steady
Assessment objectives
AO1 82%
AO2 19%
AO1 Knowledge & understanding
AO2 Apply & analyse
AO3 Design, program & evaluate
Explain86%
Identify52%
Describe52%
Complete43%
Practise its 21 questions Biggest: 7 marks · May/Jun 2025

25% of the topic's marks sit in question parts that belong to another topic (scenario questions cross sections) or that no bullet claims; they count for the topic, not for a bullet.

Marks a paper, year by year

212223242526

By exam series

May/Jun18/18 · 17.1 mk
Oct/Nov15/15 · 18.6 mk

Practise 63 real questions Smart Notes Quiz Flashcards Every topic on the Statometer

What you need to know4syllabus §1.1, §1.2, §1.3

1.1Data representation — binary prefixes (kibi, mebi, gibi, tebi) vs decimal prefixes; binary, denary, hexadecimal, BCD, one's and two's complement; converting between them
1.1Binary arithmetic — addition and subtraction with positive and negative integers; overflow; where BCD and hexadecimal are used; ASCII, extended ASCII and Unicode
1.2Multimedia — bitmaps (pixel, file header, resolution, colour depth) and file-size estimates; vector graphics (drawing objects, properties, drawing list); sound sampling rate and resolution
1.3Compression — the need for compression; lossy vs lossless and when to use each; compressing text, bitmaps, vector graphics and sound, including run-length encoding

Video lectures26ZAK's YouTube channel · play here

AS2023214 views
AS2023681 views
O LevelAS2023419 views
AS2023249 views
O LevelAS20231.0K views
O LevelAS2023617 views

Open in the video library ZAK's channel

Infographics5draw these the way the examiner expects · download as PNG

Number system conversions

O LevelAS

File size calculations

O LevelAS

Two's complement, overflow & shifts

O LevelAS

Bitmap, vector & sound

ASO Level

Lossless vs lossy compression

ASO Level

Browse all infographics →

Key terms8use these exact words in the exam

BCDtwo's complementkibibytebitmapvectorcolour depthsampling raterun-length encoding

Dotted terms are defined in the glossary.

Code help2referenced to the Cambridge pseudocode guide

Two's complement of a negative number

pseudocode Run in Playground

DECLARE N, V, i : INTEGER
DECLARE Bits : STRING
N ← -5
V ← 256 + N        // 8-bit two's complement value
Bits ← ""
FOR i ← 1 TO 8
   Bits ← NUM_TO_STR(V MOD 2) & Bits
   V ← V DIV 2
NEXT i
OUTPUT N, " = ", Bits

Run-length encoding

pseudocode §5.5 string functions Run in Playground

DECLARE S, Out, Ch : STRING
DECLARE i, Run : INTEGER
S ← "AAAABBBCCD"
Out ← ""
i ← 1
WHILE i <= LENGTH(S)
   Ch ← MID(S, i, 1)
   Run ← 0
   WHILE i <= LENGTH(S) AND MID(S, i, 1) = Ch
      Run ← Run + 1
      i ← i + 1
   ENDWHILE
   Out ← Out & NUM_TO_STR(Run) & Ch
ENDWHILE
OUTPUT Out

Playground examples5runnable programs for this topic

Denary → binary by repeated division
MOD 2 gives each bit, DIV 2 moves on; the remainders are read bottom-up.
O LevelASPseudocodeTheory in code 2210 §1.1 / 9618 §1.1
Run
Binary → denary with place values
Walk the bits from the right, doubling the place value each time.
O LevelASPseudocodeTheory in code 2210 §1.1 / 9618 §1.1
Run
Denary → hexadecimal
Same idea as binary but MOD 16, with a lookup string for the digits A–F.
O LevelASPseudocodeTheory in code 2210 §1.1 / 9618 §1.1
Run
Two's complement — negate an 8-bit number
Invert every bit, then add 1 with a carry that ripples from the right.
O LevelASPseudocodeTheory in code 2210 §1.1 / 9618 §1.1
Run
Run-length encoding (lossless compression)
Replace runs of the same character with a count and the character.
O LevelASPseudocodeTheory in code 2210 §1.3 / 9618 §1.3
Run

Assembler4programs to step through the CPU simulator

Negative results and two's complement
5 − 12 = −7. Look at the binary view of ACC: 11111001 is −7 in 8-bit two's complement.
ASArithmetic 9618 §1.1, §4.2
Run
Overflow — when the result no longer fits
In an 8-bit accumulator 200 + 100 = 300 cannot be represented. The simulator keeps the value but raises the overflow flag, exactly what the exam wants you to explain.
ASArithmetic 9618 §1.1 overflow
Run
LSL / LSR — multiply and divide by powers of 2
Shifting left 1 doubles, right 1 halves (integer). 6 ≪ 2 = 24, 24 ≫ 3 = 3.
ASBit manipulation 9618 §4.3
Run
Lower-case to upper-case with SUB #32
ASCII 'a' is 97 and 'A' is 65 — the difference is 32, so subtract it (or AND with B11011111).
ASInput & output 9618 §4.2, §1.2 ASCII
Run

Test yourself

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Quiz: Information Representation (42)🃏 Flashcards: mix this topic (49)🖼️ Number systems, BCD & two's complement (18)🎧 Multimedia — graphics & sound (19)🗜️ Compression (12)Past-paper questions (63)🔢 Number Systems Lab ➕ Binary arithmetic, BCD & shifts 🗜️ File sizes & compression (Data Lab)

Everything for this topic — study hub

Statometer — what 33 real papers say about this topic and each of its 4 syllabus bullets

What you need to know4syllabus §1.1, §1.2, §1.3

Video lectures26ZAK's YouTube channel · play here

Bit Manipulation 1 · Binary Shifts · Monitoring and Control · A/AS Level

AS Level · Uses of BCD

O/AS Level · Uses of Hexadecimal

AS · One’s Complement Representation · 1's

Number Systems 5 · Two's Complement · O/AS Level

AS/OL · Binary Magnitudes · Bin Den Prefixes · Data Sizing

Infographics5draw these the way the examiner expects · download as PNG

Key terms8use these exact words in the exam

Code help2referenced to the Cambridge pseudocode guide

Playground examples5runnable programs for this topic

Assembler4programs to step through the CPU simulator

Ready to check you know it?