On the top half of the screen is an empty field and beneath it is a empty line edit. When you type "3" into the line edit three blue knights appear on the left hand of the screen. You continue typing "+ 2" and two red knights appear on the right hand side of the screen. Hitting the enter key the knights all trot into the middle of the screen and the colors turn yellow giving you five yellow knights.
Using other operations makes for a more interesting view. "3 - 2" will result in the knight fighting until there is only one left. The same goes for division. Multiplication is a bit more tricky. The family friendly version could have the knights calling for re-enforcement's while the adult version could use animals rather then knights and they would just multiply after a quick climb over each other.
When you add parenthesis the groups would be divided up and you could watch the different divisions attacking to see which color survives in the end. It could either do a random all for one mess that results in the correct answer or the divisions attack in the proper mathimatical order.
This is all about eye candy so there would be many different types of creatures. Subtraction could be Trolls that come over and club or even have arial planes that bomb before flying off screen. Given a little intelligence it would be a lot of fun to watch. The battles didn't need to be short, a long calculation with big numbers could take a long time.
From the Square One TV show, a skit with a similar premise as Calculator wars :)