Ever noticed the iPad doesn't come with a calculator? Well - with multicalc, you get not one, but a few of them (and for good measure, they'll work on your iphone as well - or vice versa)

This is easily extensible, so I'm open to new calculator types, but for the moment, the following are provided

* a simple calculator
* a tip calculator
* a reverse-polish calculator

You can change calculators just by swiping to the one you want.