You are looking for a truly challenging math puzzle game, something new and better than the same old, same old. Enter Sumurai Pro, 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 Pro provides five levels - from the (somewhat :-)) gentle Easy level to the terrifying Champion level. Start with the easy level and work your way up to the harder levels. Some champion levels are so hard that it took us hours to solve.

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 spin. If you want to try a lighter version (with only easy and medium levels), try the free Sumurai app.