Add math action to life total counter

First love this app. Best one I have found and been using it for months now as a frequent player. I play mostly multiplayer games and I have frequently hit situations where players combo off and gain insane amounts of life or play cards that double, etc.

Would it be possible to easily add a math option for a total you set. My idea would be to replace the click life total pop up with a checkbox. Default show the current "type amount" text box you have now, but add a checkbox/radio button that says something like "calculate" or "arithmetic" and when check show three text boxes.
Text box 1: defaults to your current life total
Text box 2: Drop down list that contains arithmetic operator: (+,-,*,/)
Text box 3: number to perform on first text box defaulting to blank

User fills in all three boxes and hits ok, window closes and life total of player life selected is the resultant of the arithmetic.