This is just a quick-n-dirty calculator - er, umm, 'Quickelator'.
I'd personally use it in a helper class of sorts, and pull the variables out within a controller to define the restricted variables for use, but for now, because I'm unsure as to the 'reason' for choosing a framework for such a simple task - i'm open to committing this at least for now.
In between the busy (post-Easter break) phone calls, and catch-up from too much ham :) - I'll see if i can quickly incorporate this as a helper/library class - framework agnostic in opinion, I'll venture to put it within Zend (though i've never officially used Zend, only other [ahem!] less verbose frameworks ;).
If one (wink, wink!) really wants me to put this into a framework setup (ie, controllers, models - though there wouldn't be much there ;), views, etc...) "someone" could express that thru "Rachel". Ie, is CodeIgniter a good enough OOP?