It is useful to think of binary in terms of columns. The first column represents units, so a 0 here means no units i.e. 0, and a 1 means 1 unit. The next column represents the numbers of 2s, so a 1 in this column means 2. The next column represents 4s and so on, with each column being twice as big as the previous one. This is also what we do in denary, each column being a factor of 10 bigger than the previous one. So the denary number 2902 can be interpreted as (2 x 1000) + (9 x 100) + (0 x 10) + (2 x 1). If you want to convert binary numbers to denary, this is a useful method. For instance, if I wanted to convert the numbers 1000100 and 11001 to denary I would make a set of columns as shown.
Figure 1 Conversion of binary numbers to denary.
NOTE:
This has been copied and pasted from the T171 web site.
