Introduction17
Sections 1 through 3 elaborate on the subject of calculating manually. Section 1 tells how to set the display and how to enter data in scientific format. Section 2 tells how to use the addressable registers and to manipulate the stack, while Section 3 tells how to use the built-in functions.
Section 4 covers the subject of programming, telling how to revise (edit) your programs, how to have them repeat themselves, to stop themselves, to make decisions, etc. The programming section also illustrates the use of the program worksheets shipped with your calculator.

The HP-65 Quick Reference Guide

The guide summarizes the more important procedures given in this handbook and explains the key functions, arranged in order of keyboard symbol for ease of reference. Use the guide to check details. It can be carried in the soft case.
If we have not answered all of your questions, contact your nearest HP office, or, if you are in the U.S., dial (408) 996-0100, and ask for Customer Service. We want you to be completely satisfied with your HP-65.