Rock Ridge Games has released Solution Zero for
the iPhone and iPod touch.It's available at teh
Apple App Store
(http://itunes.com/apps/solutionzero) for US$1.99.

Here's how the game is described: "Counteract
mushy-mind syndrome and stay sharp this summer
with a heaping helping of Solution Zero's
brain-building challenges. The object of the game
is simple: complete on-screen equations by
dragging operators (+, -, x, √∑) between a set of
six numbers until the solution equals zero. The
total will update as players slide operators
around the touch screen, offering a clear picture
of their progress. In each round players must
tackle ten equations, and will earn points based
on number of "zero solutions" achieved, as well
as how quickly the equations are solved. Players
can also track their high scores and watch as
their arithmetic intellect improves."

Designed by a Mensa member and video game AI
author, Solution Zero offers four levels of
difficulty. Future game updates will feature an
online leaderboard, where players can compute and
compete against other puzzlers worldwide.