Better is to use the 'double and add the next digit' method.
Consider an easier example first.
1011 -> 8 + 0 + 2 + 1 = 11
Start with the 1 at the left hand end, double it and add the next digit, 2*1 + 0 = 2, double that and add the next digit, 2*2 + 1 = 5, double that and add the next (the final) digit 5*2 + 1 = 11.
Try another one, 110101 (-> 32 + 16 + 0 + 4 + 0 + 1 = 53).
On paper, it's usual to set it out in a column
1 1
1 1*2 + 1 = 3
0 3*2 + 0 = 6
1 6*2 + 1 = 13
0 13*2 + 0 = 26
1 26*2 + 1 = 53.
If you look in 'Sticky Topics - Great Questions to Learn From', there's a note regarding the conversion of decimal to binary, this is the reverse operation.
- Bertie
