Fixed amount or fixed rate discount/premium calculation in an electronic cash register

An electronic cash register comprising:

• setting means for selectively placing said cash register in either a presetting mode of operation or a normal regristration mode of operation;
• a first function key operational in said presetting mode for setting said cash register in a fixed amount discount mode and a second function key opertional in said presetting mode for setting said cash register in a fixed rate discount mode;
• memory means responsive to said first and second function keys for storing a signal representing either said fixed amount discount mode or said fixed rate discount mode;
• discount instruction input means operational in said normal registration mode of operation for instructing said cash register to perform a discount calculation;
• and
• control means responsive to said discount instruction input means and responsive to said signal in said memory means in said normal registration mode of operation for conducting either a fixed amount discount calculation or a fixed rate discount calculation.