# iGCSE Computer Science - Distance Learning

Course Information
Data Representation (Number Systems)
Text, Sound, & Images
Data Storage & Compression
Tutor Marked Assignment 1
Communication & Internet Technologies
Tutor Marked Assignment 2
Hardware & Software
Tutor Marked Assignment 3
Computer Software
Tutor Marked Assignment 4
Data Security
Tutor Marked Assignment 5
Ethics & AI
Tutor Marked Assignment 6
Algorithm Design & Problem Solving
Tutor Marked Assignment 7
Programming (Python)
Tutor Marked Assignment 8 (Programming)
Databases
Mock Exams

# Converting Binary Numbers

As part of the iGCSE, you will be required to convert binary number to and from denary, our base 10 number system.

We’ve already seen that binary uses powers of 2 to convert from Denary (base 10) to Binary (base 2), and using the conversion table below is a useful way to help you to convert as you will not have a calculator in your exam:

`128  64  32  16  8  4  2  1`
` 0   0   1   0   1  0  1  0`

In the table above, we’ve converted the number 42 into binary by placing the powers of 2 in different columns and placing a 1 under the numbers that you would use to add up to 42. So in this case: 32 + 8 + 2 = 42

We can use this process in reverse to convert a binary number back into denary by writing the powers of 2 over each digit and adding up the columns with a 1 in. If your binary number is longer than 8 digits (bits) just keep doubling the numbers in the columns!