How to play Cross Numbers

Fill the grid with numbers so every across and down answer fits its maths clue, sharing digits where answers cross. Also known as Crossnumber, Number crossword, Cross figures.

▶ Play Cross Numbers ⊞ Open the solver

The rules

Each white square holds one digit; each answer reads across or down.
No answer starts with 0.
Clues describe the number (a square, a prime, a multiple of 7, its digit sum…) or link it to another answer.
Where answers cross they share the same digit.

Playing Cross Numbers on Puzzle Solvers

Choose a size and a difficulty, then press New Puzzle.
Tap a square (tap again to switch between across and down) or tap a clue, then type the digits — the cursor moves along the answer.
Clues get a ✓ when your number fits them (links to other answers check once both are filled in).
Hint fills the next answer that can be worked out and explains how.

Open the Cross Numbers game →

Using the Cross Numbers solver

Send a puzzle from the game, or press Sample.
Press Solve and step through: the numbers each clue allows, and how the crossings and links pin each answer down.

Open the solver →

A worked example

1 Across is a 2-digit cube: 27 or 64. 1 Down is a 2-digit square starting with the same digit: 25 (with 27) or 64 (with 64)…

If 2 Down crosses the second digit of 1 Across and is a multiple of 5, it can’t start with 7… so 1 Across = 64.

Strategies

Short and special. Two-digit squares (16, 25, 36, 49, 64, 81) and cubes (27, 64) give very few options — start there.
Use the crossings. If 1 Across must start with 1, 2, 3 or 4 and 1 Down starts with the same square, 1 Down’s options shrink too.
Digit sums. ‘Digits add up to 3’ for a 3-digit number allows only 102, 111, 120, 201, 210 and 300.
Multiples. Multiples of 5 end in 0 or 5; multiples of 9 have digits adding to a multiple of 9.
Linked clues. ‘2 Down × 3’ means once you know 2 Down, this answer is fixed — and the other way round.

Common mistakes

Starting an answer with 0.
Forgetting a digit is shared between two answers.
Mixing up square numbers with multiples of 2.

Where it comes from

Number crosswords — also called cross figures or crossnumbers — have appeared in puzzle magazines and newspapers since the 1920s.

Frequently asked questions

What does ‘3 Down × 4 − 2’ mean?

Take the answer to 3 Down, multiply by 4, then subtract 2 — that’s this answer.

What is a palindrome?

A number that reads the same both ways, like 4554 or 121.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

Can I enter a puzzle from a book?

The solver explains puzzles made here; it can’t read printed clues, but any generated puzzle can be sent to it.

Keep going

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