Regardless which platform you are using, theres bound to be a calculator included in the stock OS. For simple calculation, these calculators work fine, but if you want to do more complex calculation, like solving an algebraic expression, it wont make the mark.
I just posted my first application to the Google Play Market.
It is called QOS Tip Calculator. It is a tip calculator that allows you to factor in the quality of service you received from your server to determine the tip. Its a novel idea in my opinion, and for all I know it is a fairly unique idea...
Went to open Calculator the other day, in Win8.1, on the desktop. Clicked Start button, got to start screen, clicked the down arrow to get to all apps, found Calculator, and BAM, full-screen Metro app. Totally useless to me.
So I finally found the "right" calculator, if you hit Winkey+S (for Search), then type Calc, you get not just one, but two listings for calculator.