You are looking for a truly challenging math puzzle game, something new and better than the same old, same old. Enter Sumurai, the world's most challenging math puzzle game. Your goal is simple: swap numbers and operators around so that they all form valid expressions.

If you can add, subtract, multiply and divide two digit numbers, you have all it takes. But like Chess, Go-moku or Sudoku, a few basic rules create infinite levels of complexity.

Sumurai provides easy and medium levels, and Sumurai Pro adds hard, expert and champion levels. Start with the easy and medium levels and work your way up to the harder levels (available in the Sumurai Pro app). Even the easy and medium levels in Sumurai can be quite challenging.

Beat your own best time at each level. Watch your math agility improve (if you care about such things).

So, go on, give it a try. If you want more challenge, get the Sumurai Pro app with even more challenging levels.