Teach Computing
Revision notes, activities, lesson plans, teaching ideas, and other resources for GCSE, A-Level, and IB Computer Science teachers and students.
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Examples of Local Cryptocurrencies
Digital Money for Local Communities covers three examples of country-wide c...
Hash function
A hash function takes arbitrary sized input data (e.g. a fil...
Cryptocurrencies vs regular currencies
What is Bitcoin and How Does it Work? is a high level overview of the Bitco...
Examples of Cryptocurrencies
Bitcoin is by far the most well known cryptocurrency. The Bitcoin website w...
Practice paper 3 exam questions
One of the drawbacks of the yearly case study is that there are no past p...
Emergency Management System Explainer Video
This short video gives an overview of some EMIS features. It includes many ...
Geographic Information Systems (GIS)
For some functionality, an EMIS may also be connected to a GIS (Geographic ...
Programming languages - from Scratch to machine code
The CS Field Guide has a very comprehensive guide to different types of pro...
Assembly language simulators
There are several assembly language simulators available for use online. Si...
Click here for recommended AQA A-Level Computer Science textbooks.
Binary-Decimal Conversions
This video contains lots of examples of converting binary numbers to decimal numbers, and vice versa. A good revision guide.
Updated: 2018-02-17
Unsigned binary arithmetic
Binary Addition & Overflow
Another excellent video from ComputerPhile with their usual clear explanations and worked examples. This video recaps binary numbers and then explains how to perform binary addition. It also deals with the potential problem of overflow and how it can be handled.
Updated: 2015-04-29
Signed binary using two’s complement
Why we use Two's Complement
This video explains how to represent negative numbers in binary. It explains why we can't use a simple sign bit to represent positive or negative numbers, and then looks at how one's complement solves this problem. Finally it explained how two's complement works and why it is used. Although the beginning of the video goes into a lot of detail, it is useful to understand exactly why two's complement is needed and used.
Updated: 2015-04-29
Numbers with a fractional part
A-Level appendix unit - PG Online
Floating point numbers, adders, D-type flip flops are covered in this free lesson resource unit from PG Online. The presentations and activities are designed for the AQA AS and A-Level courses, but the content is relevant to other A-Level courses too.
Updated: 2017-10-17
A-Level only content
Absolute and relative errors
Normalisation of floating point form