Pen-based Calculator

New Scientist is reporting about a nifty calculator program that recognizes handwriting (see the demo movie):

They were surprised to find that people using ordinary calculators got the wrong answer 51% of the time. [...] For example when working out the answer to 4 x -5 it is easy to end up with the answer -1 instead of the correct answer of -20. People using the new device, by comparison, got wrong answers only 19% of the time and this was due to inaccurate character recognition, an error that is easy to spot and so correct.