Calcudoku Mathdoku(Sudoku)

‘Calcudoku(Mathdoku)’ - More Than 1,00,00,00,00,00,000 Calcudoku or Mathdoku puzzles A perfect Calcudoku or Mathdoku is here for all sudoku lovers with amazing 4 different difficulty options i.e. 'Intermediate','Challenging','Tough' and 'Expert'. Options 1 to 4 varies from very simple, easy to hard and toughest game play. The game is similar to Sudoku but uses a little math. Thick lines indicate 'cages'. Each cage has an arithmetic puzzle which must be solved by the digits in the cage. e.g. '8 ' means all digits in that cage add to 8. The order in which digits are used is irrelevant Features-
 1) 4 difficulty options with 1,00,00,00,00,00,000 Calcudoku or Mathdoku puzzles 2) Different grid sizes - 5x5, 6x6, 7x7,8x8,9x9
 3) Pencil marks with auto fill / erase
 4) Undo and Redo 5) Intelligent hints 6) Selected digit highlighting 7) Incorrect entry highlighting
 So get ready to be puzzled...