MathsCross

A crossword made of sums. Fill the grid so that every row and column reads as a
correct equation, across and down at the same time.

Every puzzle is generated on your device, so there is nothing to download and
nothing to wait for. The app requests no internet permission whatsoever — not for
the first puzzle, and not for the ten thousandth.

SOLVABLE BY LOGIC, NOT BY GUESSING

Easy and Medium are guaranteed to be solvable by reasoning alone. Every puzzle is
checked during generation: there is a chain of steps from the numbers you are given
to the answer, and at no point do you have to try a value to see whether it works.
Nothing is left to trial and error.

That makes them suited to children of around nine and up, and to anyone who finds a
puzzle that requires guesswork unsatisfying. Hard and Extreme lift the restriction —
they still have exactly one answer, but finding it may take experiment.

WHAT YOU GET

• Four difficulties, each adding one thing rather than several at once.
Easy is a 5x5 with single digits, plus and minus.
Medium is a 7x7 with two-digit numbers and multiplication, every operator shown.
Hard adds negative numbers and hides some of the operators.
Extreme is a 9x9 with three-digit numbers, division, and every operator hidden.
• A daily puzzle. One shared puzzle a day, the same for everyone, with a streak to
keep. It changes at midnight UTC.
• Unlimited puzzles. Each one is made fresh and has exactly one solution — always
checked, never guessed.
• Undo and redo, so a wrong turn costs nothing.
• Your progress is saved. Close the app mid-puzzle and pick it up later, undo
history included.
• Statistics: puzzles completed, best and typical times, and your daily streak.
• Four themes, including a high-contrast one.

NORMAL ARITHMETIC

Sums work the way you were taught. Division and multiplication before addition and
subtraction, left to right within each. A game about arithmetic does not get to
invent arithmetic.

There are no trick questions either: no puzzle will ever ask you for something like
9 + 0, where the answer can be copied rather than worked out.

The one thing worth knowing: digits next to each other make one number. Two cells
holding 1 and 5 read as fifteen, not as one and five. Grouped cells are drawn joined
together so you can always see which digits belong together.

NO NONSENSE

• No adverts.
• No in-app purchases.
• No accounts and no sign-in.
• No analytics, no tracking, no data collection of any kind.
• No internet permission, so none of the above is possible even by accident.

Works on a plane, on the underground, and on a phone that has never been online.