How to play Number Cross
Number Cross is a math crossword: a grid of short equations that cross each other. Your goal is to fill every blank square with a number from the pool so that all the equations are true.
The board
Each equation takes five squares in a row or a column: a number, a sign, a number, an equals sign and the result. Equations across read from left to right; equations down read from top to bottom. Where an across and a down equation meet, they share one number square.
The number pool
Under the board is the pool: exactly the numbers that belong in the blanks, no more and no fewer. If a number appears twice in the pool, it goes in two blanks.
Playing
Tap a blank square, then a number in the pool. You can also tap a number first: it goes into the next blank where it fits. Tap a filled square again to take its number back. On a keyboard, the arrow keys move between blanks and you can type the number.
When every square of an equation is filled, it is checked at once: a right equation turns blue, a wrong one turns orange and counts as a mistake. Undo takes back your last move. Each puzzle has three hints; a hint fills one square and tells you why it must be that number.
The signs
| Sign | Meaning | Example |
|---|---|---|
| + | plus | 6 + 3 = 9 |
| − | minus | 9 − 4 = 5 |
| × | times | 4 × 3 = 12 |
| ÷ | divided by | 12 ÷ 4 = 3 |
Each equation has just one sign, so there is no order of operations to worry about. Division always comes out even, and every number on the board is a positive whole number.
Levels
| Level | Board | Signs |
|---|---|---|
| Easy | small | + and − |
| Medium | larger | +, − and × |
| Hard | large | all four, numbers up to 100 |
| Expert | largest | all four, and some signs are blank too: round blanks take a sign from the pool |
Tips
- One blank first. An equation with a single blank gives you that number at once.
- Use the crossings. A shared square has to fit both equations, so check the other direction before you decide.
- Count the pool. When only one number in the pool could fit a blank, it goes there.
- Work from big to small. Large results and products usually allow fewer choices than small ones.
FAQ
Is there always one answer? Yes. Every puzzle is checked by a solver before you see it.
Do I need an account? No. Your progress and stats stay in your own browser.
Is it free? Yes, and there are no ads.