Patent ID: 8423898

Claim:
One or more non-transitory computer-readable media storing instructions which, when executed on an electronic device, implement a calculator application configured for performing a method comprising the steps of: receiving a sequence of values and operators which comprise a calculation that are entered by a user on a keypad implemented by the calculator application via a user interface; implementing a virtual tape for storing the sequence and being selectively viewable by the user on the user interface to show at least portions of the stored sequence, the virtual tape being arranged as a user-accessible memory so that selected data in the virtual tape is linkable to one or more respective virtual tapes in a plurality of virtual tapes, each of the virtual tapes i) being configured to be selectively viewable by the user for display on the user interface, and ii) including a visible graphic device, the visible graphic device resembling a watermark and providing information to uniquely identify a given virtual tape; configuring the user interface for editing the values or the operators in the stored sequence on the virtual tape, the user interface being adapted for implementing a calculator time mode, the calculator time mode enabling accepting values having units of time, displaying the values having units of time, performing calculations using the values having units of time, and displaying results of the calculations using the units of time, the user interface including a user control for invoking the time mode, the user control being graphically identified using a colon displayed on the user interface; dynamically updating the calculation responsively to the editing; and showing the updated calculation on the virtual tape.