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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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...

Little Man Computer (LMC)

The Little Man Computer (LMC) is a software simulator of a simple computer ...

Lesson - Data representation - sound

This download contains all lesson resources necessary to teach students how...

Predictive placement

Predictive placement is a feature of some CAD systems that enables more e...

AI to help emergency dispatch phone operators

The Singapore Civil Defence Force (SCDF) may trial an AI system to help tra...

Mobile Data Terminals (MDT)

MDT technology is referenced in the case study booklet, with such systems b...

Resources discount offer

Binary Number System

Click here for recommended AQA A-Level Computer Science textbooks.

Unsigned binary

Binary to decimal

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

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

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

AQA A Level computer science

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

Rounding errors

Absolute and relative errors

Range and precision

Normalisation of floating point form

Underflow and overflow