Seven, five, minus. Now pop it. That's what I say whenever I get into RPN calculation, short for Reverse Polish Notation calculation, because I'm sequence challenged. Sometimes. MACalc from Apple iPhone homebrew developer may have its own unique effect on you, being a close mimick of such input methods on well known RPN calculators.

MACalc for the Apple iPhone is currently at version 0.1.6 - several version numbers shy of the prime time - but that's expected from port of the old MACalc from OS/2 that's still a work in progress. The latest build introduces aesthetic fixes and a change in the storage of user-made skins for MACalc. Such fixes include:

* fixed "decimal point" display in Settings
* the "tap area" to move from Integer <> Float is now restricted to the "display area only"

What's RPN, you ask? It's a way of entering numbers (called operands, remember?) and operators so that you could have a good excuse not to use parenthesis or brackets in complex calculator operations. It's a lot different than what you're used to on your typical Casio or Sharp scientific calculator.

Why go through all the trouble? While it was probably part of the curriculum to tell this, RPN-coverted instructors claim that Reverse Polish Notation is the most efficient way to calculate, especially for computers. It's true that using scientific calculators can accept algebraic computations with parenthesized infixes, but most calculators have a limit to how many nested operations it can handle.

And once you've hit the magic number at the middle of an equation, there's no going around it. You'll be taking calculations segment by segment once again, much like what you would do in RPN. Of course, this method will require that you have some prior knowledge in infix notations and MDAS when dealing with complex equations, but once learned, RPN will stick like a bad habit. Me? Well sometimes it forgets to bring excess adhesive.

Go ahead and try MACalc. It'll be the most authentic calculation experience for RPN-trained math drones, as well as a perfect starting ground for those willing to brave new math territory.