Math Crosswords: start where only one number is missing

A Math Crossword is a grid of small equations that cross each other, like words in a crossword. Some cells are empty. Fill them with the number tiles in the tray so that every equation, across and down, is true.

Where to start

1. Find an equation with one gap. If only one cell is empty, the arithmetic gives you the answer straight away.
2. Use the crossings. A cell where two equations meet has to fit both. If one direction allows several numbers, check which one also works the other way.
3. Watch the tray. Each tile is used once. As the tray empties, the choices for the last gaps narrow until only one fits.
4. Do multiplication and division first. They allow fewer answers than addition, so they pin numbers down faster.
5. Check both directions before you place a tile. A wrong tile costs a life.