## Numbers

**Candidates should be able to:**

- convert positive denary whole numbers (0-255) into 8-bit binary numbers and vice versa
- add two 8-bit binary integers and explain overflow errors which may occur
- convert positive denary whole numbers (0-255) into 2-digit hexadecimal numbers and vice versa
- convert between binary and hexadecimal equivalents of the same number
- explain the use of hexadecimal numbers to represent binary numbers.

- Number representation 1 – MS Powerpoint (binary/denary conversion)
- Binary number representation worksheet – MS Word

## Characters

- explain the use of binary codes to represent characters
- explain the term character set
- describe with examples (for example ASCII and Unicode) the relationship between the number of bits per character in a character set and the number of characters which can be represented.

### How are binary codes used to represent characters?

### What is a character set?

### How are the number of bits per character related to the number of different possible characters?

## Images

**Candidates should be able to:**

- explain the representation of an image as a series of pixels represented in binary
- explain the need for metadata to be included in the file such as height, width and colour depth
- discuss the effect of colour depth and resolution on the size of an image file.