Just in case any of you think I am the world's slowest programmer, I've not been feeling very well recently so I can only do bits every now and then. So this might be quite a long term project at the rate I'm going.
However there is a new version available. http://dl.dropbox.com/u/74401653/Arithbequick%20v3.jar
Now there is a no solution button. You click this button when you are convinced that there is no solution available. You will get 25 points and 1 point per tile still left on the board, which is a great way to increase your score without increasing the speed of the game. You really don't want to push that button if there is still a solution though.