CPUs are made up of billions of tiny switches. These switches can either be on or off and cannot work with the numbers we use (denary, 0-9) or our languages. Everything on a computer must be broken down to binary (0s and 1s). 0 = Off 1 = On Humans use denary numbers and It’s difficult for humans to understand binary numbers. We can convert between binary and denary numbers.
At GCSE, you will only ever work with 8 bit numbers - binary numbers which contain 8 ones or zeros. For example:
0110 1110