Data representation
Binary, hexadecimal, text, images and sound: how a computer stores everything.
Grade 6 to A Level · Cambridge Computer Science
Learn Computer Science the clear way.
One course for every class. Pick yours, learn the first chapter free, then unlock lessons, papers, tools and an AI tutor that knows exactly what you are studying.
- 3
- levels
- 113
- chapters
- 315
- topics
- 11
- tools & games
Choose your class
A course for every class, kept separate
Stage 7 is not Stage 9, and AS is not A Level. Every class has its own papers and chapters, so you never wade through someone else's syllabus.
Grades 6 to 8
Lower Secondary
Computing, Stages 7 to 9 · 0860
A step-by-step computing course mapped to Cambridge Lower Secondary Computing: computational thinking, Python, data and safe use of technology. Each stage has its own course, so every student studies the right class.
Stage 7 · Grade 6Stage 8 · Grade 7Stage 9 · Grade 8Stages 7 to 9Stages 8 and 9
31 chapters · 17 free topicsOpen
Grades 9 to 10
IGCSE / O Level
Computer Science · 0478 · 2210
The complete Cambridge IGCSE (0478) and O Level (2210) Computer Science course: Paper 1 Computer Systems, Paper 2 Algorithms, Programming and Logic, and a full exam skills course.
IGCSE / O LevelExam preparation
41 chapters · 21 free topicsOpen
Grades 11 to 12
AS & A Level
Computer Science · 9618
Cambridge International AS & A Level Computer Science (9618). AS (Year 12) and A Level (Year 13) are separate courses with their own papers, so you only see what you are studying.
AS · Year 12A Level · Year 13Exam preparationAS & A Level
41 chapters · 23 free topicsOpen
What you will learn
Everything on the Cambridge syllabus, made visual
From the first binary digit to machine learning, every topic is broken into small, clear lessons with worked examples and exam practice.
Logic and circuits
Gates, truth tables and the Boolean logic inside every chip.
Hardware and the CPU
Fetch, decode, execute: what really happens when a program runs.
Networks and the internet
Packets, protocols and how a web page reaches your screen.
Algorithms and flowcharts
Plan a solution before you write a single line.
Programming and pseudocode
Cambridge pseudocode and Python, from the first line to exam-ready.
Databases and SQL
Store, search and sort data like a professional.
Security and ethics
Encryption, threats and using technology responsibly.
AI and machine learning
How machines learn, and where the field is going.
The Classroom
Do it, don't just read it
Simulators, calculators, games, flashcards and projects that run right in your browser. Many are free.
Simulator Premium
Pseudocode Runner
Write Cambridge pseudocode, run it, and watch a trace table fill in line by line. Perfect for checking your exam answers.
Simulator Premium
Sorting & Searching Visualiser
Bubble, insertion and selection sort, linear and binary search, animated step by step with a running count.
SimulatorFree
Logic Lab
Type a Boolean expression, get the full truth table, and try the circuits examiners love.
GameFree
Binary Blitz
Convert as many numbers as you can in 60 seconds. Beat your best score and keep your streak alive.
Free to start, simple to unlock
1
Pick your class
Lower Secondary, IGCSE / O Level or AS & A Level, with your own papers and chapters.
2
Learn the first chapter free
Full lessons and examples in the first chapter of every paper, so you can try before you pay.
3
Unlock for 1, 2 or 3 years
Pay by bKash. We confirm and the whole level opens, with Pseudocode, Python and Projects included.
4
Practise with the AI tutor
Ask questions beside any lesson, get exam-style practice and have your answers marked.
An AI tutor beside every lesson
Stuck on a topic? It reads the lesson you are on, explains it again in simpler words, sets exam-style questions with marks, and marks your answers like an examiner.
Why does a computer use binary?
Because every part of a computer is a tiny switch, and a switch has two states: on and off. Two states are written as 1 and 0…
20 questions a day for every unlocked student.
Plans
Pay for the years you need
Choose 1, 2 or 3 years for your level. A 3-year plan matches the three Lower Secondary stages; a 2-year plan covers IGCSE or AS and A Level.
- Lower Secondary1y ৳1,500 · 2y ৳2,500 · 3y ৳3,500
- IGCSE / O Level1y ৳2,000 · 2y ৳3,500
- AS & A Level1y ৳3,000 · 2y ৳5,000
- Every subject, paper and chapter of the level
- Pseudocode, Python and Projects included
- Premium tools and the AI tutor
Latest notes
All updates- New free lesson: variables, input and output in Python (A Level, Paper 4)5 Nov 2026
- New lesson: IF THEN ELSE (Pseudocode)5 Nov 2026
- New lesson: operating systems (AS Level)5 Nov 2026
- New lesson: logic gates and truth tables (IGCSE / O Level)5 Nov 2026
Questions students ask
Who is CS By Monir for?+
Students from Grade 6 to A Level who study Cambridge Computer Science: Lower Secondary Computing (Stages 7 to 9), IGCSE, O Level, AS Level and A Level. Each class has its own course, so you only see what you are studying.
What is free?+
The first chapter of every subject paper is free, with full lessons. The whole syllabus map is open to everyone, and several tools and games in the Classroom are free too.
How does unlocking work?+
Choose your level and pay for 1, 2 or 3 years by bKash. We confirm your payment and the whole level opens: every subject, paper and chapter. Pseudocode, Python, Projects and the premium tools come with it.
Do I pay separately for Pseudocode and Python?+
No. Pseudocode, Python and projects come inside every level, written for that stage, so a Stage 8 student and an A Level student each get the right ones.
What does the AI tutor do?+
It sits beside each lesson, knows what you are reading, explains it again, sets exam-style questions and marks your answers. Every unlocked student gets 20 questions a day.
Is this official Cambridge material?+
No. CS By Monir is independent. Lessons are written by Monir sir for the Cambridge syllabuses.
Start with Chapter 1, free.
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