This is a cool program designed by Melanie Rust, a second grader and 8 years old (helped a little by her dad).
Although very simple, it demonstrates a lot of the programming principles, including math, useful in Phrogram.
The goal of the game is to catch the butterflies with a net. Each butterfly has an equation on it. A matching value is on the net.
If you catch the wrong equation, you lose a life. If you get all of the butterflies, then you go on to the next level which contains more butterflies.
There are 13 levels and 5 lives. Even if you know your stuff, it is NOT easy.
Check it out!