A computer operated, calendar-based financial calculator comprises a computer display, calendar calculating software, and a calculation engine, so as to provide a visual presentation of any calendar month. A key frame has an upper surface, and a key mounting part disposed on the upper surface for mounting the key supporting part of the key unit. The slide member has an input gear meshed with the second gear part. In the event of a collision between the cutting head and an obstruction, the second mount member disengages from or moves with respect to the first mount member to prevent breakage of the cutting head. At least some of the database records in the rapid access memory are summarized and stored within the rapid access memory.