RPNu

RPNu is a calculator that makes crunching numbers easier than it’s algebraic equivalent.  RPN stand for Reverse Polish Notation (The ‘u’ stands for universal, meaning it runs on both the iPad and iPhone.) and is the numeric evaluation method used for this app. RPN, I feel, is far superior to the algebraic method and once learned you will never want to use the algebraic again. 

This calculator has all the normal mathematical function, but also contains a host of other functions that you may find very useful.  Space is limited in this description but here are the highlights:

Help: There is extensive help to aid the user in determining how to use this app. It is also context sensitive.
Programable: You can write your own programs and there are many tools to aid you in doing this.
Graphics: You can graph equations and there are several modes to cover almost all requirements.
A universal converter that you will find very useful.
Matrix arithmetic (determinate, invert, add, subtract and multiply).
Date calculator and an hours calculator with moon phase display.
Elements and periodic table information.
Combinations and permutations calculator
Equation integration and root finder.
Amortization with many useful functions.
Mapping function that allows you to determine distance between points and other functions.
Hyperbolic functions.
Hexadecimal, Octal, and Binary modes.
Barometer function showing QNE and QNH.
A compass that not only shows magnetic and true north, but also shows the address you are at.

This app includes extensive support for a Bluetooth keyboard.

Also, extensive support is given to export your calculations to either email or the universal clipboard.