1. An electronic calculator comprising: a keyboard having a plurality of keys for entering information into the calculator; encoder means connected to the keyboard for generating key codes corresponding to the keys on the keyboard, each key code having a predetermined length and being generated in response to a particular key being depressed; and processing means connected to the encoder means for processing key codes, for producing a merged key code in response to receipt of a first selected key code followed by one of a plurality of second key codes, the merged key code having a length shorter than the combined lengths of the first selected key code and the one of the plurality of second key codes, and for substituting the merged key code for the first selected key code and the one of the plurality of second key codes.