What you'll learn
How computers represent all data in binary.
Key ideas
- A bit is one binary digit; 8 bits = 1 byte.
- Converting between binary, decimal and hexadecimal.
- ASCII/Unicode encode characters; pixels make up images.
- Compression reduces file size.
Exam tips
- Practise binary-decimal conversions.
- Learn why hexadecimal is used as shorthand.
Common mistakes
- Miscounting place values in binary.
- Confusing bits and bytes.