The binary number \(1001\) can be calculated in denary ... 2\)s \(1\) in the \(1\) column means there is a \(1\) Or simply add up the values at the top of the columns which contain a \(1\).

In the computer, all data are represented as binary digits (bits), and eight binary digits make up one byte. For example, the upper case letter A is 0101001. Numbers however can take several forms.