Numerical Systems
A number system is a way of expressing numbers, usually using digits, e.g. '10'. Binary is one such numerical system that is extremely important in computer science.
Binary
All data in a computer is stored as binary, 1s and 0s. Binary is used everywhere in computers, and understanding how it works is very useful.
Colours
The hexadecimal number system is widely used for example to represent colours or bytes of data, eg. 0A, or FF
Encoding
Understanding how numbers can be represented in different ways is essential for encoding data efficiently for different purposes, such as transfer over the web.