600 Calcudoku

600 Calcudoku is our main Calcudoku series: 600 full-size 9x9 puzzles in every book, across three books that rise in difficulty. Calcudoku, also called Mathdoku, blends Sudoku logic with + − × ÷, and these grids are a real step up from the small 4x4 and 6x6 puzzles in newspapers.

Pick the level that suits you. Easy to Hard starts gently, so it's the place to begin if you're new to Calcudoku or to full-size grids. Medium to Very Hard is for regular solvers who want a steady challenge. Hard to Extreme is for experienced solvers who want long, demanding puzzles.

With 600 puzzles, a single book lasts a long time. When you've finished one level, move up to the next. Once Hard to Extreme feels comfortable, Hard Core Calcudoku 500 takes you further, with nothing below Very Hard.

All three books are printed at 8.5 x 11 inches. For bigger, clearer grids, see 157 Large Print Calcudoku, and for a travel-friendly size, 240 Pocket Calcudoku.