The HP 35s scientific calculator provides professional performance for educators and business people by offering a range of highly attractive features combined with an easy-to-navigate interface. Both reverse Polish notation and algebraic entry-system logic in this calculator provide the majority of its power and accuracy. Its versatility, however, comes from 100 built-in functions, making calculating logarithms, inverse functions, and exponentials a simple task. Boasting a complete library of conversions, along with 42 built-in physical constants, you can also simplify most physics problems. With a memory of 30 KB, this calculator is also designed for reliability during those heavy workloads. If you make a mistake while entering data, the device contains edit, undo, and delete options that allow you to correct typos and produce accurate results every time. Around 800 independent storage registers also let you store equations for later retrieval to use in HP Solve. This is used but works great as you can see, I do not have a manual but you can get one online if you need one. It has been kept in this case, case shows wear but calculator looks great and clean. Just as pictured Smoke free home School - college - Hewett Packard - this is one of the most sought after calculators