This is a book of 74 programs for the HP-55 pocket calculator, a scientific calculator from Hewlett-Packard.

There are applications in the book for doing complex arithmetic including trigonometry and complex polynomial evaluation. There are other applications for doing common business calculations, such as, compounded amount, direct reduction loan, sinking fund, discounted cash flow analysis, depreciation schedules, and calendar routines. There are also applications for doing linear algebra, integration, interpolation, and analytical geometry.

Each program is presented in a consistent fashion throughout the book. There is first a presentation of a mathematical problem along with the equations to be be solved. Second, there is a table listing the program steps (codes and key entries by line number). This table also shows how the HP-55's registers will be used by the program. Third, there are examples of problems to be solved in the form of variables to be plugged into the equations. Fourth, there is a table of step-by-step operational instructions for solving the problems, each line consisting of five fields: (1) Step Number, (2) Instructions and Comments, (3) Input Data & Units, (4) Keys To Be Pressed, and (5) Output Data & Units.

About the HP-55

The HP-55 came out a year after the HP-65. The HP-55 had 49 lines of program memory but no card reader for storing and retrieving programs. Custom user programs had to be keyed in from scratch each time they were run. It had a 1-line LED display. Numbers could be displayed either in fixed number format or scientific number format.

The HP-55 was introduced in 1975 and was discontinued in 1977. Its price was $395.

I retired my HP-55 from service when I replaced it with a programmable scientific calculator with a card reader. ( )