Patent ID: 8161088

Claim:
A pocket calculator for financial mathematical calculation routines, having a keypad ( 11 ), comprising a plurality of input keys and function keys, for inputting data, having a memory for storing permanent data and volatile data, having a processor for performing the financial mathematical calculation routines and having a display ( 12 ) for displaying data, where the keypad ( 11 ) has a plurality of function keys for a capital repayment calculation routine, namely at least a first function key (P/YR) for inputting and/or determining the periods per annum, at least a second function key (N; x P/YR) for inputting and/or determining the total number of periods, a third function key (PV) for inputting and/or determining the initial capital, a fourth function key (I/YR) for inputting and/or determining the interest rate, a fifth function key (PMT) for inputting and/or determining the installments per period and a sixth function key (FV) for inputting and/or determining the final capital, where after assignments have been made to some of these function keys by inputting appropriate data it is possible for the data item for a function key without an assignment to be determined by the capital repayment calculation routine, characterized in that the keypad ( 11 ) has further function keys for inputting and/or determining data for a dynamized capital repayment calculation routine, namely a function key (%D) for inputting and/or determining the percentage dynamization rate, a function key (Z/D) for inputting and/or determining the dynamic initial installment and a function key (Z/DE) for inputting and/or determining the dynamic final installment, where when an assignment has been made to one of these further function keys by inputting an appropriate data item it is possible for the data for the remaining further function keys to be determined by the dynamic capital repayment calculation routine.