Quote Originally Posted by C_ntua
How do you sum decimals? You start from the last digit and go on.
You don't have to start from the last digit; you can start from the first corresponding digit pair too, with a little backtracking. Either way, this does not really matter, in my opinion: the fact that we can err... float the decimal point to the right when multiplying by 10 in base 10 should hold even if you cannot fathom how to actually add the numbers on paper using the given representation.