Converting string to math operator...

Hello all. I'm looking for a solution that I doubt exists, but I figured I'd ask anyway. I'm wondering if it's possible to convert a string such as "+" to an operator. I'm working on a math game where the values and operators of an equation change often, and the player has to balance the equations.

For example, an equation might be ValueA+ValueB*ValueC=ValueD-ValueE. The player can tinker with the values and they must make the equation true. The changing values works just fine, but changing operators based on variables/strings does not seem possible.

You might try using the "ExpEval Object", it evaluates strings as complex expressions.
Or use xLua to return an expression's result to you.