Converting between number bases
Quick links 
Number bases 
Converting number bases 
Units of information 
Binary arithmetic 
Character encoding 
Representing images 
Representing sound 
Data compression 
Syllabus content
Content  Additional Information  

Understand how binary can be used to represent whole numbers.  Students must be able to represent decimal values between 0 and 255 in binary.  
Understand how hexadecimal can be used to represent whole numbers.  Students must be able to represent decimal values between 0 and 255 in hexadecimal.  
Be able to convert in both directions between:

The following equivalent maximum values will be used:

It is common for the first question on the paper to be a straightforward binary to decimal conversion. If you are confident then the rest of the paper may not seem to be so much of a struggle.
Exercise
There is a worksheet that you can use to help with lerning to convert between the most commonly used number bases in Computing, base 2, base 10 and base 16. (We use Octal (base 8) as well but we'll leave that for another time.)
Here is a useful website that shows how you can convert between a number of different number bases. On the other hand here is a page.
Finally, a number base joke! Why do programmers confuse Christmas with Halloween?
Progress
Do you feel comfortable with the various number bases used so far? Binary and Hexadecimal.
3.1 Fundamentals of algorithms
 3.1.1 Representing algorithms
 3.1.2 Efficiency of algorithms
 3.1.3 Searching algorithms
 3.1.4 Sorting algorithms
3.2 Programming
 3.2.1 Data types
 3.2.2 Programming concepts
 3.2.3 Arithmetic operations in a programming language
 3.2.4 Relational operations in a programming language
 3.2.5 Boolean operations in a programming language
 3.2.6 Data structures
 3.2.7 Input/output and file handling
 3.2.8 String handling operations in a programming language
 3.2.9 Random number generation in a programming language
 3.2.10 Subroutines (procedures and functions)
 3.2.11 Structured programming
 3.2.12 Robust and secure programming
 3.2.13 Classification of programming languages
3.3 Fundamentals of data representation
 3.3.1 Number bases
 3.3.2 Converting between number bases
 3.3.3 Units of information
 3.3.4 Binary arithmetic
 3.3.5 Character encoding
 3.3.6 Representing images
 3.3.7 Representing sound
 3.3.8 Data compression
3.4 Computer systems
 3.4.1 Hardware and software
 3.4.1 Operating systems
 3.4.2 Boolean logic
 3.4.3 Software classification
 3.4.4 Systems architecture
3.5 Fundamentals of computer networks
3.6 Fundamentals of cyber security
3.7 Ethical, legal and environmental impacts of digital technology on wider society, including issues of privacy
 3.7.1 Ethical impacts of digital technology on wider society
 3.7.2 Legal impacts of digital technology on wider society
 3.7.3 Environmental impacts of digital technology on wider society
 3.7.4 Issues of privacy