That Blue Square Thing

AQA Computer Science GCSE

July 2019: the AQA CompSci area is almost complete. Most of the content for units 3-6 is now up and there's quite a lot of Unit 7 material. There's still some work to do, particularly on Paper 1 units, but it's getting there.

Data Representation - Binary Numbers

Computers are, at their heart, very complex machines which use a very simple way of storing information. It all comes down to Binary numbers - 1s and 0s.

PDF iconHow computers deal with numbers

PDF iconBinary Numbers - binary and denary - an introduction

Converting Binary to Decimal and Back Again

You need to be able to convert from binary to denary.

PDF iconBinary Numbers - converting from binary to decimal method - how to do it

PDF iconBinary Numbers - converting from binary to decimal questions

And you need to be able to convert from denary to binary as well. Which is a little harder.

PDF iconBinary Numbers - converting from decimal to binary method - how to do it

PDF iconBinary Numbers - converting from decimal to binary questions

Why Binary?

Absolutely everything that a computer does can only be stored using binary numbers. Every single thing has to be able to be reduced down to a series of 1s and 0s to get it inside a computer of any kind.

Just think of what that means:

The reason for all this is that computers just can't deal with anything else. A switch can only be on or off - it can be a 1 or a 0. Nothing else.

PDF iconWhy Binary? - some theory which reminds you why we need to use binary.

PDF iconMore Complex Why Binary? - this details some of the ways in which data storage has developed over time and some other ways in which data can be stored and transferred using alternatives to switches.

Number Bases - a Summary

The slides summarise how the three numbers bases (binary, decimal and hexadcimal) work. This is probably best left until you know about all of them and might be helpful for revision.

PDF iconNumber Bases Summary

Binary Revision Questions

Revision questions, dealing with all of the binary stuff, will appear here:

PDF iconBinary Revision Questions 1 - everything binary only

PDF iconBinary Revision Questions 2 - binary and hex