Guides · Sums

How to play Sums.

Sums is a cross-number: equations that share squares, a bank of number tiles, and one arrangement that makes every line true. Each tile is used once, and the tightest equation usually tells you where to start.

About 3 minutes · No experience needed

The board.

Equations laid out like a crossword: numbers, signs and an equals in a line, crossing where they share a square. Some numbers are printed; the empty squares take tiles from the bank under the board.

The Pocketful Sums screen with a small cross of equation squares and a bank of three number tiles below — Starter level 1. Two equations that cross, and a bank of three tiles: 1, 2 and 7.

The rule.

Every tile in the bank is placed exactly once, and every equation on the board reads true.

Tap a tile, then tap an empty square to place it. Tap a placed tile to lift it back out. The signs and the printed numbers never move.

Start with the tightest line.

Look for the equation with the fewest empty squares, or the one where the printed numbers leave only one tile that can work. Place that, and the crossing equation usually has one square left.

The Sums board with the across equation tinted and its first empty square ringed

The Sums board with the 7 placed and the across equation's last square ringed

Common questions.

Do I need to be quick at arithmetic?

No. Beginner boards use single digits and small sums, and there is no clock on you. Harder boards have more lines and bigger banks, but the method is the same: find the tightest line.

What if a tile fits two places?

Try the line that crosses it. A tile that works in one equation often breaks the other, and that settles it.