For algorithmically generated questions that have numeric answers with units it would be nice to be able to specify a Margin of error that is generated from the answer. That way it would be possible to require a minimal number of required digits, that is to allow students to answer with more digits than required without their answer being graded as wrong.
The help pages indicates, that this should be possible using the function lsu and the ? operator. It does not seem to work, though. Entering anything other than a number in the Margin of error field sets the Margin of error to 0.