Missing Digits: Math Puzzle
Crack the hidden numbers
Only for iPhone
Free · In‑App Purchases
iPhone
4■2 + ■8■ = 12■5. Guessing won't get you there — follow the carries and only one answer fits. Endless puzzles, generated on your phone.
Uncover the hidden digits by reasoning, not guessing.
4■2 + ■8■ = 12■5.
Guessing gets you nowhere. But follow the carry from the ones column,
and the answer narrows to exactly one possibility.
FUKUMEN does one thing: missing-digit arithmetic, done beautifully, forever.
■ Features
- Endless puzzles, generated on your device
From simple addition to full long multiplication with three partial-product rows.
You will not see the same puzzle twice.
- Exactly one answer, always
Each puzzle starts as a completed sum, then digits are hidden — but only up to
the point where a second answer would become possible. Every puzzle is verified
before it reaches you. No unsolvable boards. No ambiguous boards.
- Four difficulties
Easy and Normal are addition. Hard and Oni are long multiplication.
At Oni, 19 of the 26 cells are blank.
- Today's puzzle
One puzzle a day, the same one for everyone. Streaks and a calendar
keep your history visible.
- A real long-form layout
Chalk on a blackboard, set vertically the way you'd write it by hand.
Tap a blank, type a digit. The board scales up when the numbers are short.
- Quiet help
Columns that can't work out are tinted, gently — you can turn this off.
And if you're truly stuck, a hint opens a single cell.
- Records
Puzzles solved, streak, average time, best time per difficulty.
■ Who it's for
- Sudoku and crossword solvers looking for something that actually uses arithmetic
- Anyone who wants to deduce rather than drill
- Parents and kids working through missing-digit problems for entrance exams
- People building a small daily thinking habit
- Anyone who needs a puzzle that works with no signal — trains, planes, anywhere
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The developer, torankirite, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- torankirite
- Size
- 932.9 KB
- Category
- Puzzle
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- Contains
Advertising
- In-App Purchases
Yes
- Premium $4.99
- Copyright
- © 2026, Torankirite