Crosswords With Numbers!
Most of the clues are based on the answers to other clues, so for example 1 across may be Three times 2 down. The easier levels have a few clues that can be answered on their own to get you started, but the harder ones are more circular and require twists of logic.
The puzzles produced on iPad and iPad Mini are larger and more complex than those on iPhone or iPod Touch, but the smaller ones can be just as tricky.
This free version is restricted to 5 different games at each level (20 games in total), though you can play them as many times as you like.