Fair enough. Though I'd argue on "entirely solvable by pencil and paper", since the answer is an educated guess in that case and the proof that it's correct res

Fair enough. Though I'd argue on "entirely solvable by pencil and paper", since the answer is an educated guess in that case and the proof that it's correct resides in checking with the webpage. ;-) To be honest, in the same amount of time, one could also estimate the range where the answer should be and plug it one by one in the form until it validates. (which we'll call a less educated guess :))