GCSE

# Data representations

This unit allows learners to gain the understanding and skills required for the data representation sections of the GCSE computer science exam. First, learners look at binary and hexadecimal numbering systems, how they work, and how to convert between bases. Then, learners explore different coding systems and find out how text, images, and sound are represented in computers. All lessons include worksheets to allow learners to explore each topic through practical application.

### Lessons

- Lesson 1 What is representation?
- Lesson 2 Number bases
- Lesson 3 Binary addition
- Lesson 4 Binary subtraction
- Lesson 5 Binary shifts
- Lesson 6 Signed binary integers
- Lesson 7 Hexadecimal
- Lesson 8 Representing text
- Lesson 9 Unicode and file size calculation
- Lesson 10 Representing bitmap images
- Lesson 11 Bitmap file size calculation
- Lesson 12 Representing sound
- Lesson 13 Sound file size calculation
- Lesson 14 Measurements of storage
- Lesson 15 Lossy and lossless compression
- Lesson 16 Run length encoding
- Lesson 17 Huffman coding
- Lesson 18 Summative assessment