Juzu is a free puzzle app game for the iphone & ipad. Everything's in Japanese. But the rules are clear from the images.
Your task is to draw lines from 1 circle to another. The 4 must be connected to 4 circles. The 0 is not connected to another.
We've seen this type many times before. Some levels are free. After that, you have to pay 100 Yen. Not sure how the iTunes store will bill you for that.