Rule of Three в Android Market

Rule of Three (v. 1.0) Разработано Ignacio Gallegos

Did you ever think you were fooled on prices at the supermarket? How much will cost 2 gallons  if 5 gallons are 24$ ? Did you start figure out the rule of three and left it as impossible?
Now, make rules of three will be easier. With Rd3 simply enter the data and the result is automatically displayed.
Suggestions are welcomed!