A free program for Android, by SBC Games.

This is a very popular Japanese number puzzle game called Futoshiki. In this game, you are given a 5×5 grid and you must fill the numbers from 1 to 5 in each row and column so that they do not repeat in the same row or column. You can only use one number in each box, and the numbers in the grid must be in order from smallest to largest.

If you are able to fill all of the boxes in the grid, you will advance to the next level. However, if you are not able to, you will have to try again. The game will not let you fail. If you fail to advance to the next level, the game will reset your progress and you will have to try again.