Math Doku is a new challenge for fans of Daily Sudoku that requires just enough calculating to get the brain engaged.

Rather than the usual 9x9 grid, Math Doku allows the user to choose how many blocks to tackle. Those blocks are then divided into smaller sections that will contain individual numbers.

The math comes in with hints to help you determine those numbers. For example, a three-number section with a 7+ hint might contain a 1, a 4 and a 2. But be careful - you can only use each number once in each row and column of your overall grid.

The classic version of 10 x 10 will take you back to the days of Tetris as you build horizontal or vertical blocks of 10 shapes to earn points. When a row or column of 10 is completed, it disappears.

Sounds easy, right? But not so fast. 

The board fills up quickly, so you'll need to think about which blocks should go where before dragging them in.

The goal of Ballistic is to shoot at and eliminate blocks before they reach the bottom of the screen.

All blocks will move down one row after every shot you take. And each block shows the number of shots you'll need to remove it.

You'll earn extra balls by making good shots (or you can end the game really quickly with a series of bad shots). Make sure you take advantage of bounces - shooting balls through open pathways - to hit multiple blocks with a single try.

For Diagonal Sudoku, the premise is the same as the old standby numbers game. But in this version, you must be aware of using numbers only once horizontally, vertically and diagonally.

You can place notes in blocks or across the whole puzzle to help you out and use slash notes to denote numbers that cannot go into specific blocks. A friendly suggestion: Turn on the "show errors" button until you get the hang of this game.