Heh, a range card, a pen and some paper go a long way. There are some actual uses for on the spot calculation aid though. In some cases there's a lot of variables where having an app doing the math for you keeps you from having to set up a miniature office.

Not a bad idea. I've been a desktop linux user for a long while and got the N900 for the "ease and freedom" to customize things to my needs. This project would do me good, be an experience to learn from and it'd finally give me the push to learn an actual programming language to do things with, instead of hacking things up with a shell script.

Might take a while though : )