Hard Core Calcudoku 500
Very Hard and Extreme only. No easy pages.
Hard Core Calcudoku 500 is for solvers who have outgrown small newspaper grids and want Calcudoku that pushes back. All 500 puzzles are full-size 9x9 grids, and every one is rated Very Hard or Extreme. There are no easy pages and no warm-up section: the challenge starts on page one and holds to the last.
On a 9x9 grid, each row and column holds the numbers 1 to 9 once, and every outlined cage must hit its target using +, −, × or ÷. At this level the sums are only the start. You'll be comparing cages across rows and columns, tracking which combinations still fit, and using ideas such as the row and column totals rule to make progress.
The book is printed at 8.5 x 11 inches. If you'd like to build up to this level first, start with 600 Calcudoku, which comes in three rising difficulty ranges, then come back to Hard Core Calcudoku 500 when you're ready for the full challenge.
The book