Addition & Subtraction Flash Action App Reviews

I just bought this app for my first grader and I feel like it was overpriced. There are many other free apps out there that do the same thing. I need an app that divides the problems up by doubles, doubles plus one, doubles plus two, etc. to review addition facts. They also have to press enter each time they finish solving a problem which slows down their time therefore, their time isnt as accurate. I would NOT recommend buying this app until they correct that.