This guide helps you revise stylesheets (CSS) for Paper 3 IGCSE ICT . CSS is the presentation layer of a website. It controls how your web pages look: fonts, colours, backgrounds, borders and tables. HTML holds the content, and CSS holds the style. What’s inside: How a CSS rule is written: selector, property, value, { } and ; How to attach a stylesheet, and which style wins when there are several Text styles for h1, h2, p and lists Hexadecimal colours, with a colour mixer to practise Page backgrounds and table styles: borders, padding, width and border-collapse Classes, for example .highlight How to find and fix mistakes in CSS Exam tips, practice questions with answers, and a “Try it yourself” editor

Chapter 1 explains the difference between data (raw facts with no meaning) and information (data processed and given context). Data can come from direct sources, collected first-hand for a purpose, or indirect sources, collected by someone else. Information quality depends on accuracy, relevance, age, level of detail and completeness. To keep data safe, encryption scrambles it into ciphertext. Symmetric encryption uses one shared key, and asymmetric uses a public and a private key. Protocols such as SSL/TLS secure data sent online through HTTPS. Data accuracy is checked in two ways. Validation (presence, range, type, length, format, check digit, lookup and consistency checks) makes sure data is sensible. Verification (visual check, double entry, parity check, checksum, hash and control totals) makes sure it was entered or transferred correctly. Data that passes both checks can still be wrong. Finally, data is processed in one of three ways. Batch processing groups data and processes it later, for example payroll updating a master file from a transaction file. Online processing handles each transaction as it happens, for example ticket booking. Real-time processing responds instantly using sensors and feedback, for example central heating or traffic lights.

This 39-slide teacher presentation covers all of Chapter 3 (Storage Devices and Media) of the Cambridge IGCSE ICT 0417 textbook, with key terms highlighted in red and the textbook’s own photos and diagrams. It begins with secondary storage and the difference between storage media and storage devices. Part 1 covers magnetic and optical storage: magnetic tape, fixed and portable hard disk drives, CDs and DVDs (R, RW and ROM types) and Blu-ray discs, including a CD/DVD/Blu-ray comparison table. Part 2 covers solid-state storage and the future of storage: how flash memory works, SSDs, pen drives, SD, XD and CFast memory cards, cloud storage, streaming and smart TVs. Each topic ends with a “Check your understanding” slide, and the deck includes a real Cambridge past-paper question (0417/12 Feb/Mar 2018), all the textbook’s exam-style questions, Exercise 3a and a chapter summary. Answers and teaching tips are in the speaker notes.

Classroom-ready Cambridge IGCSE ICT (0417) PowerPoints for Chapters 1 and 2 every topic covered with diagrams, activities and exam-style questions. Built specifically for the current Cambridge IGCSE ICT 0417 syllabus (2026–2028), these two PowerPoint decks turn the syllabus’s own subject content into fully classroom-ready lessons, matched slide-for-slide against the syllabus and cross-checked against a leading Cambridge-endorsed textbook for accuracy and completeness.