From the developers of Puzzlejuice, Asher Vollmer, Greg Wohlwend, and Jimmy Hinson comes Threes!, a game about positional math with a sliding mechanic based around addition. You play on a 4x4 grid covered in numbered tiles, you slide the tiles around in the four face directions until addition can take place by adding two same digit numbers. "1" and "2" are exceptions to this rule, they can only be added to each other. It's a simple mechanic with a lot of replayability.
Scoring is determined by adding up all non-"1" and "2" tiles on the board after no more moves can be made. Each tile has a preset point value; the formula is 3^(face value/3). Thus a "3" tile is 3 points, a "6" tile is 9 points, a "12" tile is 27 points, etc. Thus, strategically, it's best to try and build the highest-value tile you possibly can, rather than multiple lower-value tiles.