Calculator

Action: 
org.openintents.action.CALCULATOR
Input: 
Intent extras: "X" optional initial double value "Y" optional initial secondary double value "Z" optional initial tertiary double value
Output: 
Intent extras: "X" double value "Y" optional secondary double value "Z" optional tertiary double value

Launches a calculator, returns the final value calculated by the user. See RpnCalc for an example of an app that responds to this intent.