This key facts covers Quick Reference - Number Systems within Binary & Hex for GCSE Computer Science. Revise Binary & Hex in 3.3 Data Representation for GCSE Computer Science with 16 exam-style questions and 22 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 14 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Quick Reference - Number Systems
Conversion Cheat Sheet:
| Denary | Binary (8-bit) | Hexadecimal |
|---|---|---|
| 0 | 00000000 | 00 |
| 10 | 00001010 | 0A |
| 16 | 00010000 | 10 |
| 31 | 00011111 | 1F |
| 100 | 01100100 | 64 |
| 128 | 10000000 | 80 |
| 200 | 11001000 | C8 |
| 255 | 11111111 | FF |
Common Uses in Computing:
- Binary: All computer storage and processing (machine code, RAM, files)
- Hex: Memory addresses (0x1A2F), colors (#FF5733), MAC addresses, error codes, assembly language
- Denary: User interfaces, calculations we see on screen
Practice questions for Binary & Hex
Which of the following correctly describes the hexadecimal number system?
Explain why hexadecimal is used instead of binary when programmers write memory addresses and colour codes. Give three reasons.