Digitsmith puts two classic number puzzles in one calm app: Calcudoku (also called Mathdoku) and Kakuro (cross sums).
Every board is pure logic with exactly one solution. No guessing and no luck. If you get stuck, a helper shows what still fits and hints explain the next step.
Calcudoku: a math puzzle in cages
• Fill the grid so each row and column has every digit once
• Each cage's digits must make its clue with +, −, × or ÷
• From a gentle 4×4 to 9×9, Easy to Expert
• Expert boards hide the operation: the clue shows only the number
Kakuro: a crossword made of numbers
• Each run of white squares adds up to its clue, with no digit repeated
• From 6×6 up to giant 20×20 boards
A smart cage helper
• Tap a cage or run to see every combination that still fits
• Combinations that no longer fit are crossed out as you play
• "Only way!" tells you when just one combination is left
Hints that explain the logic
• Each hint points to the next logical step and says why it works
• "Show me" highlights the squares involved
• The Technique Book keeps every trick you have learned
A daily puzzle, twice a day
• A new daily Calcudoku and daily Kakuro every day, easy on Monday and harder by Sunday
• Keep a streak going; streak freezes cover the odd day you miss
• Pure mode for purists: no helper, hints or checks
• Share your result without spoiling the board
More brain games inside
• Killer Sudoku, Futoshiki and Zero Calcudoku
• Endless mode for when you want just one more
• 30+ achievements, stats and best times
Made for comfortable play
• Large text sizes and a high-contrast mode
• Light and dark themes, a 3×3 or single-row number pad, left-handed layout
• TalkBack reads every square: row, column, cage and notes
• Plays offline, small download, and your progress stays on your phone
Free to play
Digitsmith is free with ads. You get free hints and checks every day, and can watch a short video for more. Ads never appear in the middle of a puzzle.
Optional one-time purchases:
• Remove Ads
• Expert Pack: 9×9 and hidden-operation Calcudoku, 12×12 and giant Kakuro, and every past daily
No subscriptions. Made by one developer who loves number puzzles.
Calcudoku & Kakuro number puzzles with a smart cage helper and daily puzzles.