This RPN calculator offers a choice of more than 100 solutions with five unique keypads. It has a complete help system with individual tips for all but the most ordinary functions. You can choose between fixed point, scientific and engineering notation, and select degrees or radians as required. You can print the contents of the running tape display and keyboard entry is optional for most of the common functions. The calculator uses a working register (x-reg), and a holding register (y-reg). Some of the functions available using any keypad are, Lastx, retrieves the last number that was used in a calculation, Drop, deletes the current value in the x-reg and Drops the number in the y-reg into the x-reg, x