A hand-held graphical calculator having a display and an input area is described. The input area includes a maximum of 30 keys and an input device. A hand-held graphical calculator package includes a hand-held graphical calculator for graphically displaying a user-entered expression and a user manual...http://www.google.com/patents/US7403189?utm_source=gb-gplus-sharePatent US7403189 - Graphical calculator
