Math Challenge
The idea of the game is very simple: you have to change the puzzle in an order, so that the numbers in every row and every column and the diagonal add up to the same value.
This game supports different sizes for the field, from 3x3 up to 7X7. The 3x3 is easy to solve, the bigger ones can be a challenge.
https://market.android.com/details?id=com.naxup.magicsquare